Does the number of attachments change during Invisalign?

Normally once attachments are put on they stay on until the end of treatment. The template used to place them usually includes all anticipated attachments so you only need to experience it once.

I usually put attachments on the 3rd or 4th appointment after you are used to wearing the aligners. I then can remove them later on in treatment if the movements finish early. It really depends on your Dr and you the patient. It can be a nice trick question for your Dr. Ask him if he places attachments on the first appointment? If he says yes then you know that he's not that experienced in doing Invisalign. You may want to find an experienced provider that says they are placed as late in treatment as possible..They are the ones with the real knowledge. Invisalign USA never recommends attachments on the first appointment!

Invisalign attachments (buttons) are placed at the beginning of treatment. Sometimes, towards the end of treatment, you will do a refinement (a few more trays) that may require an extra attachment or two.

Generally, attachments are placed at the initial insertion visit or at the visit after. However, the orthodontist or dentist may request attachments to be placed on during various stages of the treatment. This is particularly true of teeth that cannot have ideally placed attachments at the initial attachment placement visit. They can also make particular requests to place attachments only as they are required for specific tooth movements.
Usually, attachments will stay on until midcourse correction or refinement. They can be removed if no longer required, or may remain if those particular teeth still require movements. Your Invisalign provider should be able to tell you about all the attachments for the initial set of trays with the approval of the first ClinCheck.