Home improvement project bigger than expected  

I went to one of my rental properties today to fix a soft floor in the utility room and in front of the shower. I thought it would be a quick fix. I started tearing up the floor and realized that some of the support beams are rotten. Then looking at the floor better, the soft spot is actually a soft floor.
I completely cut out the utility room floor. Replacing it with new wood and tile. The bathroom I will have to continue tomorrow. I am tempted to tear out the shower and upgrade it since I am in there. I had to make a run back to Lowes to buy some 4x4s to add extra floor support, since the original is to soft. I will be replacing the bathroom floor with new tile also. I am hope there is are no other issues I run into with the bathroom.
Then I need to crawl under the house to remove some old wood the builders left down there. I am afraid it might attract termites and other pests. I also noticed the crawl space is very damp.
Does anyone else have rental properties they do their own work on? I have had this house for almost four years, I have not had a single empty month yet. I guess I have been lucky.