You’re literally worried about the last 1%. Stop it, unless you’re a 2:02 marathoner already.
I’ll def disagree with this. Particularly if you have arthritis or some other limiter which can be exacerbated by the wrong shoes. I’m learning this the hard way with my ankle arthritis - the right shoes make a huge difference. If I use a true maxi-cushion (and unfortunately slow and blocky) shoe, I can run with little problem at my 30ish mpw volume, with speedwork. If I use even a ‘high-normal’ cushion shoe like Brooks Glycerin, I can only do 2/3 or 1/2 have that volume before my ankles are aching to the point you simply know it’s a bad idea to continue.
The OP already said the current shoe is working well. So your what if isn’t a what if. Literally, they have a shoe that works and think by wearing something else they’ll be a better runner. This is lunacy, they just need to train.
Yeah, my problem is more that shoe companies keep changing their shoe models and characteristics all the time, and whenever I find the perfect shoe it receives counter modifications (at best, but makes it less ideal than it was) or just discontinued (i.e. Altra The One 2.5, not as good in its 3.0 version, then altogether discontinued). I have the added problem of limited availability of suitable options in Australia (third world when it comes to having access to proper range of suitable running shoes).