If youre doing one guitar, just get 4 feet of fretwire
You want heavy ass gauge for bass, but the wire is basically the same (6000 gauge dunlop is fine as bass wire).
You can cut it with wire cutters.
You can use either friction or glue; if the board is made from good wood and still holds frets well, then friction is fine. Glue is better, but more work to get in and doubly so to get out.
You will need
- a fret bender or two pairs of pliers and gaffa/masking tape. You have to bend the frets before they go in - if you dont you'll never get them to sit evenly across the fretboard. Fret benders can be bought for extortionate sums or made. I made mine by cutting a curved bit of wood with a jigsaw and cutting a groove in that with a little circular saw attachment for a dremel.
- Clippers/wire cutters to crop them close to the board.
- Rubber mallet.
- A very, very steady hand and good eye with a sharpening stone or similar to bevel the edges to 30 degrees (or near enough) OR a flat file in a suitable jig that holds the file at the right angle OR the appropriate (but expensive) tool from stewmac
- Small, fine files to smooth and slightly round off the ends.
- Standard fret leveling and crowning gear - fret leveling file, crowning files, wire wool, fretboard guard, and micromeshes help A LOT to finish it up. I'm gonna assume you've already done fret dressing and dont need a lesson, if youre doing a frefret. IMO the work of a refret, if the frets are already out, is 10% getting new ones in, 40% getting the ends of the frets right, 50% dressing the frets.
Theres potentially way more to it, depending what you run into (chipping the board, filling in the ends of the slots if the tang doesnt go all the way out, touching up the neck) and, while pretty good at dressing frets I'm still a bit of a n00b at doing full refrets (mainly getting the ends really consistent and tidy), so wait for a luthier to come a long and contradict me/add stuff I never would have thought of!