Our 2010 Mazda5 Sport (original owners) recently hit 100K miles. I was all ready to pull the trigger on new belts and pulleys from RockAuto, when I figured I would at least pop the hood and take a look at the original belts. To me, they look fine. There are three marks on the tensioner, the indicator is inside of them. Half of me says, dude, just replace the belts and tensioner and idler and drive it for another 100K mile. The other half says dude, that belt is fine. The manual says inspect the belt every 40K kilometers. Manual doesn't say anything about replacement. Thoughts?