1. I don’t think there is one exact recommendation. We have customers that reboot regularly every night as a precaution. Others run for months and months without restarting the SSP.
2. If a user is connected while the SSP is restarted will end up with a hanging transaction (private workspace) which they would need to log into after restart and either dispatch or discard (depending). If a user is in a public workspace nothing happens since changes are save at once.
3. Users can choose not to dispatch prior to a restart, and the transaction will just be available when they log in again.