That depends. Most outlets only support two plugs. Some outlets support 4. Are you using a splitter? Or a power strip? Splitters with multiple plugs can cause dirty electricity and bad responsiveness. Most of them are generally only two prong, so not grounded. Power strips are almost always 3 prong and most of them have surge protection as an added bonus.
As for the timing, a house can have electrical problems that don't manifest themselves in an obvious way until it gets worse, but it's more likely a lack of a proper ground or motherboard/PSU screws touching the case. Over time the vibration of fans can cause your parts to settle or wiggle out of place a bit. This is one reason why reseating is a basic diagnostic procedure. If you have a subwoofer or live in an area where people frequently blast low frequency music (Bass) it can happen a little quicker.