So long as you're not running into obstacles with the fins vertical or constantly dragging the fins over oyster beds, etc., they're darn tough.
We always recommend Hobie Multi-Lube for servicing the drive:
Hobie part #: 5120 HOBIE MULTI LUBE 1 OZ
Hobie part #: 5121 HOBIE MULTI LUBE 4 OZ
Here's two links that should be helpful as a general maintenance guide for keeping your Mirage Drive functioning at it's best.
Lubrication points:
https://www.hobie.com/forums/viewtopic.php?f=60&t=12576Inspection and Adjustment:
https://www.hobie.com/forums/viewtopic.php?f=60&t=12578