How about this suggestion then? Taken from A Tale In The Desert.

Introduce house deterioration. Let's say every week the house loses about 5% durability and requires fixing up, nothing too expensive but enough to make people need to spend a little time gathering and crafting for some repairs. To reach 0% durability would take around 140 days, which is a reasonable amount of time to gather materials together to help patch it up if it got that bad. At 0% add an extra 30 days for the land to become unstable that it either must be repaired or can be demolished and reclaimed. Tweak the numbers to how you think is best but I think that 170 days is plenty enough time to determine if someone is coming back to the game or not.