I do something similar to what your friend recommended. I use either old mono or old braid for backing and use about 75 yards of braid. Sometimes, after using it for a while, I remove it, reverse it, and continue until I have so little left that I cast to my knot, at which time I replace.
To decide how much backing you need, spool the reel with the 75 yards of braid alone (or how ever many yards you have decided to use. I use 75 when I buy 150 yard spools, so I can spool two reels or one twice.) I tie one end loosely to a tree limb, walk off 75 yards and spool the line, not bothering to use a knot, but just lightly taping it to the spool with masking tape, since I am about to remove it as described below. Then, I use an albright knot to tie the backing to the braid and reel in line until it's within an eight of an inch of the lip. Then, I reverse the process. I tie the end of the line to the tree and walk off all the line. Then I use an arbor knot and a little tape to attach the backing to the spool and reel it all in under slight tension.
The difficulty in this method is finding open land to stretch out all your line, but if you are trying to stretch dollars, stretching line can be worth it.
If you don't mind using a leader, you can keep from using up the braid by tying on leaders and replacing them instead of losing braid each time you re-tie a lure. I often don't use a leader, though, because one more knot is one more potential failure point. Also, some types of cover abraid mono or flouro quicker than they do braid, although rocks will cut braid quickly.
Jim
