Voltage vs life tim

Ho guys,

I want to do several designs for somebody. The designs need three TL074, a 4047, A 4066, and finally a 4013, Chip.
Now I have an option regarding the power supply for the said chips from 5V to say 15V.
What is your idea regarding to the best volatge for the said chips?
Anyway my main question is that Can I feed the said chips by say -+6V or say -+7.5V, yet be sure that they would work for years, even if the guy use them often In a day? Or It is better that lower down the supply voltage for the said chips so that Ensure thier life time?
Say I do not exceed the maximums, Is there any relationship between the supply voltage and the life time of the said chips?

Thanks in advance

dr.power said:

Say I do not exceed the maximums

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If you run the ICs within the specified limits, they will last for the specified lifetime (which is many many years).

In general the lower the supply voltage the lower the chip heat generation and therefore the slower any damaging chemical reactions and the lower any thermal stresses within the chip. Thus increased theoretical lifetime.
In practice, though, IMHO provided the chip is operated well within its recommended supply range you are unlikely to experience a noticeable difference in chip lifetime for different supply voltages.

Life

Heat is the problem so the lower voltage is better. Having said that, you will probably have a higher failure rate in your external connections than in the IC's themselves.