reset network setting constantly

I have an iPhone 5 ios 8.3 and have an ongoing problem that's been there since at least ios 7.

I am constantly having to reset network settings to keep the phone receiving notifications, mainly emails.

I've done all the regular things, restarts,restores,restore phone as new, the only thing that fixes what's wrong is reset network settings.

I have done this many many times in the past year or 2.

The phone only works properly for about 2-3 days, and then you know right away it's getting late emails, not wanting to connect, no service, not able to connect to server etc.

This is on wifi or data network, but seems to show up quicker on wifi.

Reset network settings and it works again for about 2-3 days and then here we go again.

Is there anyone out there with this problem and found a fix.

I keep waiting for the next ios update and hoping this one may be the fix!!

I'm starting to think the phone is junk!!!

The phones about 2 years old and really haven't had this thing work good ever, though lately, since ios8, I think it's worse.

Anyone else with some help would be much appreciated.

Thanks for your time

Dan