Maaser

1) When did maaser change from fruits/vegetables to 10% of your money?

>> This never changed. F&V’s are only maaser-able in EY (????? ??????? ????), and Maaser Kesafim (Money Maaser) is based on Psukim from Avrohom Avinu and Yaakov Avinu, who said that they will tithe ALL they had to Hashem. Please note that there are 3 opinions on Maaser Kesofim: 1) It is d’Orayssa, 2) It is d’Rabbonon, 3) It is a Minhag. But as in all cases, as your LOR what YOU should do!

2) Where is this halacha written?

>> The Chofetz Chaim has an entire section devoted to this, in has famous sefer Ahavas Chessed. There are numerous contemporary seforim written about this, including how to calculate Maaser in this generation (pre-tax deductions, expenses, etc.)

3) What do you take maaser off of? Is it your salary after taxes have been removed? Is it after taxes and loans have been paid?

>> Again, there are many opinions, and ask the LOR !

4) Do you have to have your maaser “paid off” by Rosh Hashana or can you build a fund with it?

>> I believe the Chofetz Chaim recommends never to go past Rosh Hashana.

5) If you are a farmer in Israel today, do you take maaser from your produce AND your cash? That would seem redundant to me.

>> As stated in #1 above, these 2 obligations are separate.