Told the tenant to call the landlord (me) to get a repairman out there.  

I would separate my manager  from my repairman and my attorney from my title company, I modulate my team and plug them in and remove them as necessary.

They said that the drywall was saturated and crumbling in an 8x12 area, and the repair man said the leak has been going on for a while, possibly before they even moved in, but I didn't notice it when I bought it.

It's going to cost $100 to have a repair man take a look and there is a chance it can't be fixed cost effectively anyhow in which case the $100 is gone.

My partner can handle most common repairs (plumbing/electrical/etc) so can shave off a % or two, but if you will be relying on an outside repairman for all, then you have to be honest and bump it up.

After myself and a trusted repairman inspected the house, we concluded that it would require approximately 40-50K to repair.  

I'm an auditor by profession, but my dad is a repairman, all the odds jobs he took my brothers and I took too.

My appliance repairman can typically fix the issue for equal to or less than the deductible on the warranty.Plus, you have the issue of keeping track of your warranties and then specifically going through the warranty company for each issue.

It cost $327 to repair it and the repairman fixed it in about 20 minutes.

I offer to send a repairman on Monday and ask tenant to manually fill the tank so the toilet will flush until we fix the problem on Monday.