Ppc confusion and general lack of knowledge

Hi fam! Newer seller here! I launched in July and had basic PPC campaigns. We’ve averaged decent sales daily and we’re okay. In sept I found a guy on fiverr and he did some keyword magic for me to fine tune my campaigns. Our sales went up but our ad spending ate the new sale’s profits. I ended up hiring him for a monthly rate to have him manage my ad campaigns for October-December. He’s asking me to re-up his services but I’m just wondering how bad of an idea it is to allow my current campaigns to just run on their own? I lowered the daily budget so we’re not hemorrhaging ad money. He says he’s adjusting them constantly but like, how much can one adjust? How much more knowledge should I have on PPC? I’m sorry if I sound like a total idiot. He says if he didn’t adjust Amazon would eat my profit.