I only have one to compare to...and have only had her for a few weeks...so take this for what it's worth.

Mine will vanish and hide for several days at a time. Then suddenly, I'll see her out and about frequently for a few days...then she disappears again. Might have something to do with getting fed and not needing to hunt again for awhile. When they're not hunting, most snakes aren't out looking for a hobby or anything.