Have the proper tools

Your skill level	Tools to own	Tools to get access to
Basic	Miscellaneous hand tools - phillips and flat screwdrivers, pliers, files, hammer (for making bad components into dust...) Simple soldering iron, 30W or less - too hot is bad news needle nose pliers small diagonal cutters rosin core solder, fine sandpaper, steel wool braid-type solder remover cheap Digital Multi Meter (DMM) with ohms, volts and current Audio Probe made from an enclosed phone jack, a capacitor, and a guitar cord.	Oscilloscope or PC based o'scope if you can. You may not need it for many things.
Learner	All that and A better DMM that also measures transistor gain, maybe measures capacitance. A test oscillator for driving signals Solder sucker	Oscilloscope or PC based o'scope (like through a sound card)
Advanced	All that and an oscilloscope if you can at all afford it.	Oscilloscope for certain
Wizard	All that and an oscilloscope for sure. Maybe a distortion analyzer.