Hello, I’m working on a design using AT89C55WD PI (industrial with watchdog) as the heart of circuit, the voltage is stabilized by LM723.It reads a serial 16 bit A2D, do some calculations and drives some stepper motors. It works perfectly fine right now and even when I debugged it for a week under normal conditions there was not a single bug or failure, but the design is very serious and is supposed to work this way for at least 10 years( 12 hours a day), of course it’s not for aerospace or life support ;-)but it shouldn’t have considerable failure rate. I don’t know why, but I’m a little bit suspicious to AT89S52 but as I said it has worked perfectly fine, it is also cheap and I have no evidence against it. I’d planned to do some extra tests on circuit, like voltage stress, heat stress(maximum temperature that this device will encounter will be something like 48 C, normally much lower, it also has a cooling fan) do you really thing these extra tests are necessary(if you think extra tests is a must tell me what tests do you recommend for example 10%vcc voltage stress )??? or I should do better with my extra excess time! In general how much I can rely on datasheet ? Some of Atmels are made in china, some in Malaysia some in Taiwan do they differ in terms of reliability ? Thank you very much in advance.