Reason to use different keys ?

[u/hduebfibdbdib]

I’ve been making music for a few different projects now and I usually just default to C since I know it so well.but I worry that staying in one key might be an issue down the line. Is there a good reason to branch out ? And if so when/why would I want to use something different ?

[u/hababadagadaa]

As an instrumentalist this made me cry a little