I agree with kwun, "it depends...." Previously I used to buy a 200m roll of BG80 and used 5.10m for mains and 4.40m for crosses = 9.5m/racket when stringing Yonex Standard 4knot. Today I am lazy and by 10m packages from MBS chopping them in half (copying master Kakinami). I think you should be happy to get 21-22 stringjobs from a 200m roll = 9.1-9.5m/stringjob. You will only save $7USD to get one more, better be safe than sorry and don't try to save a penny. /mats
Yesterday I had to strung a Forza 96 holes racket for a client. To be honest 10m had been very tight to do the job.