Here are three simple things that I often find during a home inspection that most homeowners could fix.
Gutter downspout extensions
One of the most common things I find during a home inspection is missing downspout extensions. The downspouts from the gutters dump the water right next to the foundation. The whole idea of the gutter is to collect all the rainwater from the roof and to get it away from the foundation.
When you put all that water on the foundation it can provide pressure and in return, you can get water in your basement. If you have a block foundation it could even be worse.
Insulate the attic access
Huge amounts of moisture go up the attic access from the home. This moisture can cause mold in the attic.
Another problem without insulating the attic access, a huge amount of heat loss go into the attic also.
Insulating your attic access is a really simple process. Even just adding batts of insulation above the access will do the job. You can also find at Home Depot a kit that is built already that fits all different size openings but most common the one would pull down stairs.
Dishwasher High Loop
All the dishwasher manufacturers recommend a high loop with the drain from the dishwasher. I would say on average 70% of the dishwashers I see do not have a high loop.
It is a very simple fix and all you need is something to keep it up and beside the sink. If the check valve on your dishwasher is not working correctly you could be back siphoning stuff out of the drain into your dishwasher.