Welcome @doughtaker! There are no hidden penalties to your REP from not being active enough or too much self-voting. If you're not active enough, your reputation score will simply stay the same. If you vote a lot on your own posts and comments, you will simply reward yourself proportional to the amount of SP you have. Your REP and reputation score will not decrease unless you are flagged for any violations (plagiarism, abuse, spamming etc.)