Conventional braces need a visit to the orthodontist every five weeks or once a month. This is the optimal interval for adjustments with standard braces held with elastic ties. Coming in more often doesn't speed up treatment, because the bone needs time to adapt to the new position of the teeth. If you can't get to your orthodontist on time, it's no problem to stay on your current archwires for a little longer – your teeth will keep moving, just at a slower pace.
With some bracket systems, such as Damon self-ligating braces, appointments can be scheduled every two months.
Aligners need less frequent check-ups – usually once every two to three months, depending on the stage of treatment and whether additional procedures such as stripping (interproximal reduction, IPR) are needed.
This answer is for general information. Your own case needs an examination by an orthodontist.