My kids are done every fall. My equine dentist checks the babies as weanlings, the checks again as yearlings as will do anything necessary, most work begins at 2 and onward so now would be good to begin. Better to avoid any future problems.
I have ALL of my horses checked every year - even the weanlings because I can get an idea if there is a potential for problems in the future. I've been working with Gary Fluhr for the last several years. If they don't need any work...no charge.
Typically, though, they don't need much work until they turn 3 when some (not all) have difficulty shedding their caps. Usually it is the older ones (4 plus) that need points and sharp edges floated. If you have one that you plan on driving, you might as well get those wolf teeth (not all horses have them) pulled before you start bitting them.