Battery Questions

Looks like my 2008 needs its second new battery. Starter motor was noticeably sluggish after a 20 mile ride and last time that happened the battery gave out completely a week or so later.

Battery tender jr. I have an 08 , still the org. battery. I had an 02 same story. I,m sold on them.
You need to check the charging system unless you let the bike sit for long periods. Still on the factory battery on my '08.
Good advice everyone. Thanks. I did have the rectifier replaced a couple of years ago. The bike is only ridden once a week or less, but it's always on a battery tender when sitting. I live in Dallas, so the garage is at 100+ degrees much of the year (not sure if that makes a difference). Anyone know of an easy way to make sure my charging system isn't knackered without going to the dealer and having it checked?