I've noticed a few people mentioning they charge their 12V frequently/every night. Is this due to batteries running near end of life or good practive when Fas'ing or P&G'ing a fair bit? I haven't had any trouble with my battery until lately when it took a few turns of starter one morning (which was a bit unusual!). My car doesn't give me 12V battery level unfortunately on my Ultra-Gauge so I haven't really got a clue what battey level is. My battery is coming up for 6 years old - what do you guys think?