Pros
You don't really have to do any physical labor, and there's long stretches of time where you really don't have to do anything at all. In terms of actual work it's a very undemanding job.
Cons
The pay is absolutely abysmal. You start at minimum wage, if you want to make more than that you have to jump through a lot of hoops, and completing the necessary training and getting more certs isn't going to help. They only let you advance when management feels like letting you advance, which is basically never. Customers are the worst part of the job. I'll be blunt, the people who come in parts stores these days are incredibly stupid. Smart customers just buy stuff online, or are in and out so fast you don't even notice them. You will be dealing with complete idiots all day. Most customers who came in our store weren't even smart enough to buy auto parts, much less install them on a vehicle. Simple questions like, "What's your make and model?", "What's your sub-model?", "What engine does it have?", and "What SIZE hose/clamp/line do you need?" are enough to completely stump 75% of customers. It's ALWAYS your fault btw, when you get them the wrong part even though they themselves had no idea what part they need, for what vehicle. I was a mechanic, have ASE certs and all sorts of knowledge about repairing cars, and I thought that would be a benefit in this job. Nope. Customers are NOT interested in fixing anything properly, they don't have the time or the brains to learn either, everything is the fastest and cheapest method available. You'll spend a lot of your time explaining that using compression fittings on brake lines is not only illegal, but very unsafe. Doesn't matter though, that's what they want and they'll throw a fit if you don't sell it to them. Good luck trying to explain the right way to repair things too, they'll look at you blankly and then whisper that you're full of BS to their girlfriends as they leave the store. I really lost heart in the job when I started to realize that high school age kids, who know nothing at all about cars or parts, do just fine at this job. You just teach them to agree with whatever the customer says, hand them whatever it is they ask for, if they're looking for advice find out what it is they want you to tell them, say that, and they'll be happy. Or at least, they can't blame you when anything goes wrong, because it was all their idea. This might seem cynical, but it really is the smartest way to go about this job. I'm just not the type of person to lie to people all day, even when they seem to prefer you to do it.