I'm with daox. There's a lot of fear monger's especially when it comes to cvt's. In case you didn't know there are 2 cvt filters. I'd at least change the paper cartridge one on the side of the transmission once in a while. The cvt fluid smells burnt and rank from new. Factory stuff is bluish green, the "wrong" stuff I've been using for years is light brown like engine oil.
If your fluid is constantly dark after a few changes then you may have something going on in there. Make sure you have the proper fluid level.
View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 36.7 mpg (US) ... 15.6 km/L ... 6.4 L/100 km ... 44.1 mpg (Imp)