Lack of appointments

I feel like I haven’t had many appointments for my pregnancy. They are like every month but that feels so spaced out now that I’m in my sixth month lol when do they start to get more frequent?! When do they start to tell you how your baby is growing? Ive had three ultrasounds, will I get more towards the end of my pregnancy? Is that how they determine size?

Sincerely,

FTM