What is a registered agent, and is it worth paying for one instead of being my own?

You've basically got it. In my state you can be your own agent if you have an in-state street address and you're there during business hours, which, if you're mobile all day, is the part worth thinking about rather than the fee.

Two of my three businesses I was my own agent and it was fine for years. The third I paid for, for exactly one reason: I was spending three weeks at a time out of state, and the thing about service of process is that it doesn't care you were busy. Missing something that arrives that way is a far more expensive problem than the annual fee.

If you're home most evenings and the truck stays in one county, be your own. Revisit when that stops being true.

I'd push back on one part of that. My business address is my house, because my business is literally my house, and what nobody warned me about is how public that record is. Within a month of filing I was getting mail addressed to my LLC from people who had clearly pulled the state's list, and one of them turned up in person to sell me insurance while I had four children here.

For about $60 a year I'd have kept my home address off a searchable list. For a mobile detailer working out of the house I'd weigh that before the convenience argument. It isn't a legal reason. It's a stranger-knows-where-you-sleep reason.

Both of these are right for different reasons, and one more from the real estate side: whoever you name, put the annual filing date in your calendar the day you file.

I've watched agents lose good standing on an entity because the agent address went stale after a move and the state's renewal notice landed somewhere nobody checked. If you're your own agent, catching that is on you, and the remedy is a reinstatement fee plus paperwork. Not dramatic, just annoying, and entirely avoidable with one recurring reminder. There's a tax calendar here that I ended up copying my own state dates into.