It's cool if you're not down with spending $100 on a battery. Everybody has their reasons.

So from a $100 (at Costco) Optima to a 42$ battery for your Tii. Do you think it will last 5 years, or will you spend another $42 in 2.5-3 years so $84 is a good deal?

I have a 5 year old Optima myself and I hate swapping batteries that barely make it out of warranty. My time is worth more than $12, gasoline to get it, and the aggrevation of dealing with dead batteries.