Courtesy the good folks at http://www.guitarspecialist.com/

It’s a little known secret that mere mortals can repair and maintain their instruments using only hand tools (sssh, this is just between us!). Heck, using prefab or custom-ordered necks and bodies, you can build them too. Contrary to popular opinion, you don’t always need a ton of unwieldy and expensive tools to work on, if not fully build your own guitars at home. And let’s face it, your apartment manager might not be down with you installing a drill-press in your living room. Mine said no way, at least. For some reason they tend to frown on that. Not sure why.

I’d do this in my kitchen, but what to do about that pesky sink?

If you’re lucky enough to have home with a garage or storage area where you can set something like that up, go for it. Most basic tasks, however, can be accomplished even in your apartment with items you can get from a trip to your local hardware store and electronics supply shop. Obviously if you want to get more seriously in depth into things like fretwork, you’ll need to hit up a reputable guitar shop supplier like Stewart-MacDonald for specific files, crowning and shaping tools and whatnot, but a lot of the items for general repairs are available anywhere. For the purposes of discussion here, let’s assume you’re the daring type that wants to dive in, so we’ll try to cover most of, if not all the bases.
It goes without saying you’ll need a variety of Phillips and flat-head screwdrivers, but you’ll also need an assortment of Allen wrenches (yes, more than just the 2.5 and 3mm ones that came with your Floyd Rose!). And probably one of the greatest investments you’ll ever make (not just for guitar work but around the house in general) is a cordless power drill/driver. I have a Black & Decker model I love, but Makita and other manufacturers make great ones too. Get a full set of drill bits because you never know when you’re going to need them. Diamond-tipped bits are more expensive but won’t wear out as fast either. Get a couple of small rasps while you’re there, too – you never know when you might need to slightly widen an access hole or clean up some flash left behind from someone else’s shoddy job. Of course, get sand paper and sanding blocks, and always keep a stash of #000 steel wool on hand for cleaning finger-cheese and gunk off fretboards.

“Clamp! Solder! Sponge!”

Get C-clamps of various sizes – big enough to secure your guitar’s body to your work surface for drilling or routing, and maybe even to secure the neck to the body while drilling for a neck install. A Dremel moto-tool is also on my shopping list. They’re extremely versatile and handy tools to have around. They also make the Trio, a 3-in-1 cutting/sanding/routing tool, and both would be great additions to any home or apartment lab! With those two tools, the proper templates and locking router bits, one could conceivably accomplish pickup and bridge cavity mods at home, especially if you already took a shop class in high school and/or have some basic woodworking skills.
You’ll need to visit your local Radio Shack or other electronics supplier for the things you’ll need to do your own wiring: a soldering iron with a holder/cleaner (30 watts works for minor guitar repairs), flux, rosin-core solder, and a wiring kit with multiple spools of colored wire so you can color-code your wiring schemes. A multimeter is a great thing to have, and can quickly answer head-scratcher questions like “Is it my wiring job that’s funky, or is this Ebay pickup’s coil dead?”, gauge the output of a pickup, etc. It’s always good to keep a supply of spare potentiometers (250 and 500k I like CTS pots), capacitors of the desired values for single-coil and humbucking pickups, switches and input jacks too. Oh yeah, push-pull potentiometers (also 250 and 500k) if you want to wire humbuckers to split for single-coil usage, for example. I’m kind of a parts pack-rat personally. You never know when a component is going to fail, so why not have it on hand and save yourself further time and trips to the store? Sure, you can’t predict everything, but chances are most electronic issues are going to involve a faulty pot, switch, or jack, so it just makes sense to keep spares.

“Put some Duncans in me. NOW.”

You’ll need to figure out what you’re going to use in lieu of a workbench if you’re in an apartment and don’t have a proper one; this usually ends up being my kitchen table or counter top depending on the job. This is where the C-clamps come in handy, again. There are a number of commercial guitar pad/neck rest devices like the FretRest Guitar Maintenance System, or you can make one out of wood scraps from the hardware store and a small section of carpet remnants. But in a pinch you can even lay a towel down to protect the body’s finish, and use a rolled up newspaper for a neck cradle. Once you’ve decided how deep you want to dive into your own repairs, you can come up with the tool shopping list that best suit your vision for your own mad (guitar) scientist lab!

The Stew Mac Guitar Repair Parts Tray – admit it, that’s just cool.