I'm in Thailand on a 30 days visa exempt. I'm planning on heading down to Jomtein immigration to extend it tomorrow, which is day 20.

Is it ok to extend it 10 days out?

Yes.

has a tm30 been done

 

9 hours ago, steve187 said:

has a tm30 been done

 

You should ensure that the place where you are currently staying did file a TM30.

If that's a Hotel, then should be OK.

If you stay at a friends, you can file a TM30 on his/her behalf by taking a copy of his/her housebook with you and a copy of his/her ID-card. 

If you are hiring a condo, and the landlord did not file one, you can also do one on his behalf (same documents + rental agreement).

In the latter two cases it's possible you will be fined for not having been reported. 

Edited September 23, 20196 yr by Peter Denis

... and by all means avoid the 'services' of the legal agency located next to the Jomtien IO building. 

The last 2 times I extended I was told 7 days is the earliest it can be done. I was sent away and told to come back at 10 days. YMMV