for me, i don't pay zakat pendapatan - if you guys are talking about the monthly payment type
my basis is that would be like "double taxation"
i pay RM## every month, then every one year I pay RM ### - calculation which includes money from the balance of my salary (of course, the full calculation includes my savings and all other whatever la). so i just pay once a year.
on a more religious stand point, i follow the ruling that there is no such thing as zakat pendapatan (monthly payment type). there is only zakat maal (zakat harta), calculated and paid on an annual basis.
the common and logical argument that supports this is that in the old days of the Prophet (PBUH) and sahabat, there are already people who work and earn salary. it was never known that these people pay zakat on a monthly basis.
one can, of course, argue that the monthly payment is like dividing your yearly zakat by 12. fine, la. but i just think it's premature to pay when really, you need to ensure that your harta meets the criteria of having a full year (hijri year) completed where the amount exceeds the minimum threshold (equiv to 85 g of gold, iirc). full year means the amount never drops below 85 g of gold. if it drops, the counter should reset upon the time the amount recovers. it's also like trying to stay ahead of fate (takdir), as if you already know what will happen (i.e. that you will meet the full year and amount criteria). who knows, we might die the next day and therefore we are liberated from the obligation to pay zakat, since we did not complete the full year cycle.
but that's just me and what ruling i hold on to. not trying to force it upon anyone.

means kalau dah bayar zakat wang simpanan, tak perlu bayar zakat pendapatan ke? (from i understand its the same buf the diff is pendapatan is like wang simpanan bahagi 12)