Replacing pc

A lot of clients asked me when they need to replace their pc. Should they get a new one when old pc cannot work anymore?
I will ask how long they can work without a new pc. If they can work without a pc for a week, I will just recommend backup data and wait pc die. If they always need a pc, I will recommend they even need some backup pc sitting aside. When pc get old and even it can work well, I still will recommend they should replace them.

Testing cannot be done by programmers only

If a programmer tells me, he/she tested their codes, I would consider that is not completely tested. I am a programmer too, I found we will test the codes following our own logic. It won't find the bugs we have not considered all. So, the codes need to be tested by another team. Also, that is good to test by some general users, they test the programs completely out of technical context. This way can find some very very uncommon bugs.