Just how I've done it...
Up until the beginning of '04 we trailered our boat. So it always sat in an Illinois driveway even during Winter. And we've owned it now (and '88) for 11+ years.
I had always stored, and towed, with the drive just short of all the way up.
Just so any precip could run out the drain plug while in the driveway and no shot skeg due to the terrible roads in this state.
All the bellows and seals were fine after all those years.... no leak problems whatsoever.
When our second tilt issue arose, one that I was not capable of fixing myself, and I asked our shop to replace all the bellows and seals. They also agreed that it was time. Coulda made it another 2 years max.***Forgot to mention that th tilt issue was because one of the exterior drive tilt hard-lines corroding...not any bellows stuff****
If someone is telling you every 2 years, they're blowing smoke up yer arse. Maybe in saltwater...