Ask if there is a waiting period before the benefits kick in. I just looked at dental at the end of last year and several plans had waiting periods before coverage would start although some covered routine things like cleanings from the start but more major services had a waiting period.
THIS.
I'm having to pay nearly $4K out of pocket for a root canal and post & new crown. Due to all the downtime during the worst of the pandemic, I had to switch to a cheaper plan with the same insurance company. What I didn't realize was it is such a crappy plan that my primary care doctor and my dentist, both whom I love, do not accept that plan. Reading various online reviews of doctors and dentists who do accept that plan, they were worse stories than any Stephen King horror novel.

So, while I had insurance coverage, there was no one that I wanted to be in their "care."
I was going to switched to a different & better insurance company that my Dr. accepted. However, that plan's dental only covered a root canal, post & crown after being on the plan for
3 years. Only generic check ups and cleanings, X-rays and a few other procedures added per year until year 3.
I finally chose a third company which my Dr. accepts that had open enrollment for a few more days. Better dental plan. However, this plan only covers a post & crown when the root canal was already done by one of their dentists covered by the plan. By this time, I had the root canal already done by my regular dentist, as I was in so much pain.) I decided to choose this insurance anyway as I get more (needed) medical coverage with my doctor and other future dental benefits.
I am having to pay out of pocket for ALL the $4K dental as I realized I really want to stay with my dentist's office to do the whole procedure. (They had done a root canal & crown about 20 years ago, and I've had no problems with it. I'm hoping for the same with this new one.

) They have worked with me and created a payment plan, so I can pay them directly and out of pocket s.l.o.w.l.y. and with no tacked on interest fees, like I would if I had to put it on a credit card.
Anyway, I found out all the info about what the different insurance companies' plans, benefits and doctors/dentist who accept those specific plans are via the different insurance websites. Nowadays, that info is all online and have the benefits & dentists laid out for each plan. It was all open access. I did NOT have to be a member
first and input some membership number to get the booklet or coverage info or doctors participating for the plans I would have.
Just do a Google search for: insurance company + specific dental plan. It will hopefully bring up the info.
As a follow up, to make sure the info is up to date. Call your dentist to make sure they do accept that plan. And call the insurance company and speak to a rep to make sure you are truly covered for the procedures you need. I would not have found out the stipulation I needed the root canal done by them first,
then get the crown - which IS covered, if I hadn't called. I would have seen the website saying they cover crowns, and have thought it was covered.
(Same for you, if you already had some work done. What will this new company cover of any on-going and new procedures? Also, one company said it would still cover me for a number of weeks if I was in the middle of some procedures. I think that is the law here in NYS, that even if my coverage is terminated, I can finish out certain procedures (for a certain number of weeks) before being forced to a different insurance company.
The rep did say, I could have the crown done by one of their dentists and then put in an appeal, asking that the crown be covered as the root canal had been done before I became a member. But, that was too iffy. I could still have been denied (after having it done,) and it wouldn't have been done by my usual dentist. That's when I decided I'd rather pay out of pocket.