The one very important thing that Huf mentions that I think should be expressed to all new builders who dream of building full time is the cost you MUST sell your work for to sustain yourself. At least in America I would guess $30,000 - $35,000 a year is the minimum you need to make to live comfortably. That means you must take home at least $3000 a month after you subtract parts, materials, tools, and overhead. All of those push your price up at least $500, usually more. That is figuring if you can work out of your garage or basement. If you have to rent a space to work, that's at least a few hundred more a month you need to bring in. After figuring in all of the costs I would say $3500 is minimum you need to sell for to live off of, if not $4000. That means either 1 $4000 guitar a month or 2 $2000 guitars a month.
You are very unlikely to become rich off of this business which is why I think a lot of people revert to working it as a part time job/hobby. I remember Perry saying at one time that it took him several years until he started to turn a decent profit.