time to do this as the birds will be checking out roosting sites now, ready to set up home in march. always make sure the box faces north or east, as a south-facing box will get too hot in the summer.
don’t underestimate the importance of hygiene. research shows that disease can be spread from bird table to bird table. try to clean the table every couple of weeks, sloshing with hot water and spraying on a weak bleach solution before rinsing with cold water. 