The "sweet spot" is the ideal point where you get the highest performance (and quality) at an optimum price. It can refer to many types of goods, but electronics are of particular interest because of their phased lifecycles and planned obsolescence. There's the old joke that by the time you've bought a computer, it's already an antique — and while that's not quite so true in an age where even a low-end PC can do basic 3D gaming, sweet spots still exist.

The word "ideal" here isn't without context, as technology keeps moving forth, and it's always worthwhile to refresh yourself every quarter to be aware of what trends are coming down the line, and what previously unattainable electronics are no longer such a distress to your pocketbook. So keep that in mind, keep moving, and here's some tips to keep close:

Search Amazon.com, eBay, and Newegg to discern the best price-per-part

There're other sites, but no matter where you end up buying from, you'll go right using this trinity. Let's use a solid example: Secure Digital cards, which once were specialist forms of memory, but thanks to their proliferation in digital cameras, MP3 players, and other gadgets, they're common. Sizes go up to 32GB, but which size is the sweet spot?

First, a little research: the higher-capacity ones are specifically known as SDHC (Secure Digital High Capacity, which makes sense). So you'll want to search for that. And what gets revealed?

• Amazon.com - Their search engine has iterated from one generation to the next. As of this writing, simply typing in "sdhc" will autocomplete and reveal the 2nd-most popular search is "sdhc 16gb", a useful clue. If you just search for "sdhc", among the top matches are 3 Transcend-brand cards for 4GB, 8GB, and 16GB.
   
    
   
  32GB cards exist, but they're upwards of $100, which clearly puts them out of the running, since you could buy a stack of 16GB cards @ $30/each for that price. From initial inspection, you might think the 4GB is the "sweet spot", since it tends to have the lowest cost-per-gigabyte. However, that isn't the only factor; the sweet spot is largely about finding the price point before a sharp spike to the next-highest model. Thus, we have tentative confirmation on 16GB.
• eBay - Highly-useful feature here: many categories, including electronics, are subdivided sensibly. Try searching for "sdhc 16gb" and you'll see something like this on the left-hand side:

   

  (Something similar also shows up for RAM and hard drives.) Wow, look at how many 16GB cards there are compared to the others. Evidently, there's market demand. Sometimes it isn't so clear, but in this case, we have a winner. Looking at eBay's own "Buy It Now" prices shows 16GB SDHCs to go for about $25-30, around the same as Amazon, so you know short of a surprise deal, this is a choice price.

• Newegg - This is perhaps the geekiest of the 3, because it focuses on electronics. A quick search here can reaffirm what you've also already learned on Amazon.com and eBay. Also, note that like Amazon, Newegg's search shows "Best Match" (sometimes known as "Relevance") by default, so scanning the first page of matches is a helpful overview to establish you're on the right track.

The "sweet spot" is also about quality

An component of quality is "convenience". No one wants to save their money on unusable junk. Continuing on the SDHC trail, further reasoning why 16GB is generally the best choice here: it gives you convenience to pay a few extra bucks, rather than be annoyed by swapping smaller-sized cards repeatedly. Some devices have limitations which can't use higher-spec cards so be sure to consult the manual, but for the sake of simplicity, it's a good guideline.

In other words, don't skimp on several dollars if spending them will save you time & trouble. Which can't be replenished, unlike money.

Browse popularity lists

Yes, the "sweet spot" is amidst a popularity contest. Why? High-volume sales facilitate lower prices. A wonderful example of this is the Intel Core 2 Quad Q6600, the first "quad-core" processor to break into the mainstream. I remember hearing a rumor that the prices would be slashed 50% in mid-2007. I didn't buy after the drop actually happened. Thanks to this and other factors, the Q6600 became a very hot chip. It wasn't the fastest at the time, but that's another lesson:

There's almost always a hefty price premium for the "best" model

Often, #2 is "deluxe-priced", too. Then, a steep exponential drop downwards. Whether that premium is worth it depends on your needs. The Q6600 adhered to this rule, with the Q6700 and "Extreme" X6800 costing significantly higher. But with all those Q6600 sales, the prices came down even more, and it kept topping the sales charts. It happened to be a very nice performer at a very nice price. From its debut at $850 to its current tag at sub-$200, that's substantial change in a year-and-a-half.

Graphics cards are another area where #1 is loads more costly than #2 and #3. Like CPUs, double- or triple-price doesn't necessarily mean that much more raw results. There's a big leap between a great midrange performer like the GeForce 9800GT ($130 or less) and the GTX285 ($500, and graphics card numbering is seriously confusing, but that's another story). And by extension, whole computer systems containing "#1 parts" (which will soon be #2 in a few months, if not already) rack up the charges. Which is why you'll see the same "sweet spot" parts (like the Q6600) used in so many factory-built PCs.

If you can't wait because you believe purchasing now will give you a cumulative advantage in the long run, then go for it. E.g., if this gear is for business and will increase your profits. But if it's merely a mindset of wanting the "latest and greatest for its own sake", I encourage you to look deep within yourself before dispensing dollars.

HDTVs are commonly prone to this spenderlust, and I've held off on buying one because I don't feel the price/performance ratio at this time for, say, a 42" 1080p model justifies my entertainment. Yet.

Popularity lists (Part II)

Besides computer chips, digital cameras are another great gadget to trendify. If you're thinking of buying one, Flickr has a Camera Finder which graphs their popularity, as measured in pictures taken with those digicams over time. If you cross-reference this with Amazon.com and others, it's no surprise there's a strong correlation between the most popular and the best value. For example, the Canon Powershot SD1000 and its sequel, the SD1100 IS (which I own — I practice what I preach), which are #8 and #9 on Flickr's current list, right after the #1-7 domination of the much higher-priced DSLR models (which are arguably popular to a smaller, professional audience):

And don't forget Amazon's most popular electronics, which is one of the best overviews out there. (Remember: even if you don't buy from them, you can get info about the same products you'd purchase elsewhere.) Another plus: popular items also have a high amount of reviews, allowing you to make a more informed buying decision than obscure pieces which may be good, but aren't as supported — that's a risk you take. If there are undiscovered gems, speak praise loudly so others will be enlightened. Altho it's highly unlikely the manufacturer will give you a retroactive discount, helping your fellow WiseBreaders is an awesome thing to do.

Numerous other sites have their own popularity lists, and since no one is all-authoritative, running multiple searches and observing patterns will all bolster your knowledge.

Be aware of sales cycles

This includes not just "those times of the year" like holiday season when prices are lowered to make way for new stock, but also ties into industry events like the Consumer Electronics Show where the latest and supposedly greatest is debuted. For the Mac faithful, there's been Apple's presence at Macworld, although this year was their last. Still, I don't know a Macaholic who'd buy a new Mac days before an Apple event if that model hadn't been refreshed in a year. Become familiar with your preferred companies' sales cycles.

The end lesson is the same: you can't hold off forever, but if you're a couple of weeks or less from new products being announced, you can likely wait. Even if you don't buy the newest versions, you can save on an older model which is very capable — perhaps it was yesterday's "sweet spot" and no longer is, but may serve you just fine.

The above only contains Amazon affiliate links to "sweet spot" products I have bought and used extensively. I'm a strong believer in only recommending what I have direct experience with.

Do you have advice for finding the "sweet spot"? Let us know!