My tool kit is about the size of a toiletry case. You know the compact type. 1 knobby handled screwdriver with a whole bunch of screwdriver heads. Magnetized, of course. A basic computer toolkit for maintenance and upgrades is what I recommend.
I may do a minor job like installing memory or adding an optical drive, but never more than that. Anything that takes more than an hour get taken back to my shop.
I offer free diagnostics to my clients, if they drop off their computers and I'll call them to give them the quotes, recommendations and give them choices.
My tools are minimal. I don't repair components. I replace them immediately. Nobody takes out a soldering iron anymore. It's cheaper, faster and less problematical to switchout, replace, exchange and the like. Fancy sets of tools for every occasion doesn't mean practicality, it means you're spending money in the wrong areas. If you want more info, pm me. Have a good one.