If you want a really really good hack, it can take years. For one that is reasonably basic, then it takes months. It depends on the hack and the hacker, as well as what you want to include. ASM heavy hacks take ages due to the knowledge needed or the work, whereas small script edits and graphics take a shorter amount of time (depending on the scripts). So it depends.
So, if I found a song on YouTube or have a song that I like as an mp3 (I'm not asking to use mp3s in the game) would there be any way to put those songs into the game?
Dang...I've seen people who get together on here and make hacks, how would I go about possibly getting some help? Cause I know that since my hack is FR it wouldn't take as long as a Black and White hack, but I do have a lot of ideas for it and I don't want it to take too long. :/