The secret to success as a mechanic is not learning what to fix,
it's learning what NOT to fix.
Do not fix the spring bolt in a belt tensioner.
Do not fix gas-shocks.
Do not fix self contained struts, at least, not without spring tools
Do not remove the pin from the hood hinge on a 32 ford....
Do not ever,ever, fold up that little sheet metal tab on the Chrysler ignition switch
Never let the smoke out, it is very hard to put back in...