Are they worth it?
Sometimes discounts come up for ~$175.

 

depends on what processes are involved for that $175
if justs a wash and high glossy wax, it aint worth $175 of your hard earned money.

 

and skill level

 

Supposed to clean the interior too.

 

I'm assuming you mean the dealer and like Justin said it's probably just wax and fillers. Might last you a few months at least. Much rather take that money and buy the products myself and do the job. That's what I did a few years ago, ended up buying a Griots dual action polisher, pads, M105, M205, collinite 845 wax and now I can do/fix most things on my own.

 

No dealer, 3rd party. ie https://www.groupon.com/local/auto-detailing

One time the dealer was doing something, left windows and glove box open, came back with pollen, leaves and other debris in my glovebox that's still there.

 

Either way, unless they're including at least 1 step of paint correction, I don't think it's worth it. But it's your time/money so that's your decision.