I would be especially concerned in an older home that showed evidence of non-professional electrical work. A multimeter will tell you more about the electrical characteristics of your house, but is probably overkill for most people. Wire stripping tool. Don't buy the cheapest one you can find. A good one will strip the wire cleanly and easily and not scratch the wire.
Some models have a place to insert stripped wire and shape a loop to go one a terminal.
A good, cheap way to make sure the wires are dead before you work on them. A lamp or radio works too.