Is setting aside a specific amount from one's salary with the intention of giving it as charity considered a Bid'ah (innovation)?

There is no harm in accumulating money from one's salary with the intention of giving it as charity and spreading it widely. Charity is prescribed at all times, and reminding others of it and encouraging it is also prescribed at all times. The Prophet, peace and blessings be upon him, encouraged charity on numerous occasions, which does not negate its permissibility at other times. The fundamental principle is that charity is permissible at all times.