problem with the coils

I have an 81 750h been running for a while now. The problem is I seem to be going thur coils about every 6 month.
I hve been buying the stock ones because money is a little tight. I know this is not normal.so I must have an electrcal problem.
Anyone every had this happen. Where is a good place to start looking. Have to leave now but will check back later.
THANKS FOR THE HELP GUYS
jim

I would do the ignition system checks outlined in the manual.
also check the charging system. not sure if that would be causing the coils to fail or not, but the bike does need a good, fully charged battery to run right.

Manual. 750Turbo.com. 1980-84 KZ750-4 1983-85 ZX750 pdf manual. good pdf scans. 750turbo.com --- Index
there is a complete manual, plus sections of the manual divided into 15-20 pdfs but those may be incomplete.

Make sure the regulator is holding the system voltage at 14V. If it is going high, it will kill coils.

I hve been buying the stock ones because money is a little tight

Used or new? Old coils die quickly.