Best Practice for Charging Spare Battery

Best Practice for Charging Spare Battery I know that with lithium batteries your charging routine can impact battery life. I have two batteries. When it's time to replace the active one, I exchange it with the spare. What's the best practice with the spare when it comes to extending its life? I can think of three possible options: 1. Leave it charging until it's needed. 2. Leave it discharged until shortly before needed and charge it then. 3. Charge it right after removal from the doorbell. Then do a "touch up" charge right before use. Thanks.