Would it not be cheaper in the long run to get new membranes Spruce?

I have an old ro-man , had the membranes in 4 years now, change filters 3 times per year ( american ones now)
the water is 220 in and 002 out, never used resin , it used to be 00.0 until recently , so i will keep an eye on the membranes.
So i would say they are still no cheaper than anywhere else with or without a pump , sounds like its all chinese to me.
I think the 300 gpd from pure freedom is the best , reasonably price one on the market , at the moment.