How many times can I change my apple id

You can change it as often as you want. Some people have had problems changing the address when they use their iCloud address as their Apple ID.

Apple hasn’t published any guidance for using the same address again. Normally, if your e-mail address was associated with an ID in any way, then it can't be reused with another Apple ID for approximately one year. I have also seen posts that stated Apple told them there was a 30 day waiting period before the address could be used again.  You will need to get another e-mail address to use as your Apple ID or you can try waiting 30 days to see if that works.

Change or create a new ID? Device or computer? If trying to create a new ID on a device, from the article below.

Any single iDevice creates up to a maximum of three iCloud accounts, and these accounts are linked to your iDevice’s hardware, not your Apple ID account.

The maximum number of free accounts have been activated