No one abuses cars like I do. I have tried tenders, but they scared the hell out of me. So I try to start them and run them through the winter. Drive them around town when the roads are clean. But, from time to time the batteries get low and I put a charger on them to bring them back up. I don’t jump start them at all. I haven’t had any problems doing this. I am not sure what causes the dreaded skreem problems, I just hope it doesn’t happen to me. I haven’t had the sticky key issue yet, but the roadster is getting touchy. I never hang anything on the keys. Just the fob. I haven’t ever lost any settings. Even my dashdaq keeps working. Just keep good voltage in the batteries. And keep up on your reading in the search areas. A lot of electrical gremlins can happen. If you have ever seen a totaled XF with the dash out, you will see thousands of feet of wiring....lol