It really amazes me that people keep on asking this question over and over and over. Some people will claim that they have a 505 and never had problems (1%). Others will tell you about their 505/506 woes and problems (the other 99%).
The best advice that you can possibly follow is this:
You have a device that has a VERY HIGH chance of failing. Ignore anyone who tells you otherwise. You have two options to avoid this:
1) Do a warranty replacement BEFORE you start experiencing problems. Just say that you are having random reboots (even if you are not).
2) If you can't use the warranty because you're not in the original country (i.e. Taiwan), then sell it on Craigslist/Kijiji/eBay as fast as possible, while it is still working. And then buy one from someone else with a later production date.
In the meantime, you should be backing up everything on your phone to the cloud (google drive) automatically, so that you don't lose any data when your phone does fail. Google Photos, SMS Backup+, Titanium Backup (set it to backup daily while you sleep).
If you don't backup everything, you only have yourself to blame when that day comes...