Re: Nokia Lumia 635 keeps resetting around 3-4 time a day
Constant resets throughout the day mean there is a hardware issue with the phone. Did it get wet? Or has it been doing it since you bought it? Getting it wet will void the warranty, and dealing with resets would be the most fortunate circumstance out of what can happen.
If you have a microSD card installed, and if the phone worked for a period of time before it started acting up, then it could be that you installed one of the many "fake" SD cards that are sold through various retailers. It fills up to a point, then begins corrupting the data, causing OS errors and reboots. Uninstall any apps on the SD card and move them to the phone. Then, remove the SD card and reinstall the apps on the phone. If this fixes your errors, then you had a bad SD card, and the phone should be fine to continue to use. Get a new, valid SD card for the phone.
If you aren't using a microSD card and the phone hasn't been dropped or gotten wet, then I would recommend having this phone repaired/replaced under warranty.