After sometime, (1 year) i look at my program which i thought finish, but reminiscing i could do better... finally i knew it's only alpha stage, quick hake, not optimized.
It was my first attempt to make something usable, and it is, no bug, it does what it says, - but no more. Now, i look at it in the scarring attempt to change 1 variable, but this is mission impossible. After a while i know : The only way is to take apart this big SUB which has grown up to a monster, by the many quick attempts to add some fixes, etc.
This SUB cannibalized everything because i wrote GOSUBs inside. But writing SUBs oblige you to think carefully about every variable, more than GOSUBs because a SUB is a self with takes only the variables one give it.
Now the only way is to take outside the BIG SUB every thing i can, hoping to simply the problem and taking control over the variables. Hence getting maintainable code.