[Ash.]

I do this, i have a 10 minute timer to save data, i also run a check on a 60 second timer that runs after the data save timer to make sure the players data corresponds to what was saved, and if not, it saves it over the incorrect data

It doesnt cause lag, i even run a timer to save server information to file, to be called by a website or a data request (to keep the actual server process free from extra processing)