xd675x how often do you suggest having this rechecked?
Hard to put an actual spec on it but here's what we've been letting people know:
Every 2-3 years, ~30,000 miles, or if you hit/bump something and can tell it's not aligned anymore. Which ever comes first.
Treat it like maintenance - regular oil changes, tire pressures, angle drive oil, alignment, loose nuts/bolts, battery, battery connections, etc.
Your Sling will be happy and give you many miles of uninterrupted fun!