My doctor wanted to check mine bc my pregnancy is immediately following a miscarriage without a period in between, but I actually declined. I have an U/S scheduled for Dec 2 (probably ~6 weeks then), and knowing the hcg levels between now and then won't really change anything. Numbers rising appropriately nwould provide only minimal peace of mind. Numbers not rising appropriately would probably still lead to me having the Dec 2 U/S unless I had a mc before then. Either way, it just seemed like more stress than comfort, and my doctor was okay with the decision.
In my previous two pregnancies, I called the doc at about 5 weeks and the first appointments were scheduled for around 9 weeks with no additional testing in between.