The only Milestone products requiring annual fees are XProtect Corporate and XProtect Expert. For these you do need Care Plus for the first year, but it is not required to renew, so there are no recurring fees as the first year of Care Plus is paid for up front. Then at the end of the year you can upgrade at no additional cost, even if you opt out of renewing Care Plus. Future upgrades can be purchased if wanted/needed via different methods including trade-in or Care program renewal.
All other Milestone VMS versions have neither annual fees, or a requirement for one year of Care Plus.
XProtect Professional, Professional+, Expert and Corporate are all multi-site as well, and as mentioned above, Device Pack upgrades are always free and come around every 2 months.