Man of Honour
Specsavers use lower quality coatings than more premium counterparts, like Vision Express (you pay for what you get). The lens coatings start to yellow within 18 months of using the glasses.
However, if you use them regularly, the chances are they'll start to fall apart before then anyway.
Specsavers shift volumes at low cost. Independents and Vision Express sell fewer, more quality.
I've been wearing glasses for 18 years and never had a pair start to yellow - even the $15 ones I got from Pakistan....