It kills me to see a home that is beautiful on the outside and then find mold taking over inside. Most of my friends who know me, know that I'm a pretty tidy human being. I am also a real estate professional who knows how important it is to maintain your number one asset.
Good for you, Mr. Homeowner. You fooled your neighbors by keeping up with your grass and the front of your home. Shame on you for letting the back of the home fall apart and for destroying the interior.
There are many types of mold that can easily be cleaned if you catch them early. If you sense a mold problem in your home, go out and purchase a dehumidifier. I talked about affordable ones in the past. When you see mold growing on your ceiling in your bathroom, kitchen, basement, utility room, etc. get out some bleach cleaner and start spritzing! It's not expensive and it's easy to solve before it gets out of hand.
If you knew that just by cleaning the spores could mean selling your home, would you do it? When mold shows up during your home inspection, the purchasers will ask for remediation or they could walk away entirely. According to MoldBlogger, you might be forced to pay anywhere between $500 to $4,000. and that doesn't include major damages. (http://moldblogger.com/mold-removal-cost-what-you-can-expect-to-pay/)
Pay attention to what needs to be done at your home. If you cannot afford to keep up with it, it is time to move.