I have lived in this house for 12 years without any electrical issues until now. This started a couple of days ago where the power will go out for half the house and then come back on right away or not come back on till hours later. When the lights went out I immediately checked the breakers but non of them were kicked. I did see several of the breakers that where the clasp that holds the ground wire, that the clasp was extremely rusted. I did change out several of the breakers, including the ones that were heavily rusted. But the problem persists. Since breakers were never properly identified on the door of the panel box, I and my fincee used walkie talkies and as I switched each breaker off, she would move through the house identifying which breaker that one was for. What we found was that the breakers that are affected on both sides of the box. The breakers affected are towards the bottom of the rows and the upper ones are not affected. This has not only been confusing but also very frustrating.
This is typically symptomatic of "losing a phase" and you should contact your power company to report an outage - there's very like a loose connection which is more commonly on their side of the feed than yours, (and if they can rule out theirs, you know where to have someone look if they won't look at it) and they normally respond very promptly if there's not some other major outage going on.