Each year at this time I take a good look at what’s state-of-the-art in computer terms. I’ve got budgets to use up at the schools where I teach, and I’ve got to use the money wisely. And with the economic downturn, who knows if I’ll even have a budget next year.

When you spend money on computers, you want to buy what’s right, and you’d hate to waste money, too.

That goes doubly so when it comes time to upgrade. It’s become fashionable to just throw it out. If we’re in for a recession, that may no longer be the best course.

You should consider, as I always do, upgrading individual parts rather than whole systems.

For example, I don’t need a new keyboard, mouse, monitor, printer, scanner, or speakers for any of my systems, at home or work, or for my school programs, for that matter. Chances are you don’t either.

When it comes to upgrading, you should zero in on what you need and buy only that. What’s more, you should follow my golden rule: Shop six months behind the curve. State-of-the-art is often three to four times as expensive as what it costs to buy the stuff just after the bloom comes off the rose. It’s still great stuff, though.

Yet, for many people, the deal breaker for home upgrading is not knowing what or how to upgrade the components that will deliver what you need for the future. That doesn’t mean you shouldn’t try.

There are real deal breakers, however. One is case type. Some older computers came in proprietary shapes that are baffling to take apart. Nowadays I see more stock cases on the ready-to-wear shelves at Costco, Office Depot and Best Buy. If you’ve got one of those, usually called mini- or mid-tower, you’re in luck. They’re easy to open up for parts upgrade.

Next, people wonder what tools are needed. Generally speaking, a small Phillips screwdriver is all you need. Newer cases can be taken apart by hand and have screwless adapter card expansion slots.

The most popular parts for upgrading are memory, hard drives, CD/DVD drives, graphics adapters, microprocessors, and motherboards.

The biggest performance upgrade, dollar for dollar, is memory, or RAM (random access memory). It’s not hard to figure out what type you’ve got and whether you have room to add more.

Assuming you can open your case — usually by removing a couple of Phillips screws and sliding the side panel off — you can easily locate the memory modules on the main circuit board called, for whatever reason, the motherboard.

The memory modules are about an inch high and four inches long. You can remove them by pressing down simultaneously on the levers at each end of the module.

Each module almost always has its specifications printed on a label on the side. An example is 256MB DDR 400MHz PC-2700. Let’s say you have two of those and you have two extra unfilled slots.

Go online and, using Google Shopping, buy two more identical modules, searching by specification. When they arrive, pop them in the unused slots, pressing down on each corner until the levers snap back in place. You’ve just doubled your memory, and that’s a powerful upgrade.

Next week, we’ll move on to hard drives and more.