I rotate mine between the bike and the riding mower during the cold months. Btw, you can buy extra Tender leads from WalMart if needed...I leave them on every bike I end up selling.

 

Is part of my routine now. Ride, park up in garage, hook up tender.
When the bikes in storage when salt goes on the road its hooked up all the time. I've had three HD's with tenders and never had any issues.