What rocket scientist told you that? Cause if he can predict motherboard failures then he can predict lottery numbers for next week!
I've had motherboards that I ran 24/7 for 5+ years with the only problem of them getting slower as the software gets bigger.
In fact my system that I'm replying to you on is getting to near that age! except the video card that I purchased in January!
Best of luck..JQ
I would just lock a few extra dollars away each payday as the "when it goes dead fund" and hopefully by the time this machine goes you might have enough cash to build a much faster system!
JQ