If you call a company that ONLY does drain cleaning, not only are they better at it, but they have no incentive to to encourage you to replace the pipe.If it does turn out that you need to replace the pipe, it would be due to deteriorating condition.

so even if the underlayment has deteriorated and is causing the roof to leak it can't be considered a repair expense not an improvement?

The kids' former living situations deteriorated, so it's not empty between our visits to rent for furnished TDY housing afterall. 

If it is gradual wear and tear then I would expect you the landlord to pay for it otherwise I would expect them to do it.Example: if this were a door that no longer operated properly is it because the door has gradually deteriorated over 100 years or did they kick it open in a drunken rage?

Overall the house was in descent shape on the inside but I knew there was some issues with the exterior from visible signs of deterioration.

This will cause rapid deterioration of the shingles.

Starting in November I decided that I would give 10% of my income to whatever good causes I choose, and I am looking forward to eventually making a big impact this way. 3.GrowthIf you aren’t growing then you are deteriorating.

@John Salgado sorry, no experience with sewer mains, however based on that photo, the deterioration and staining, my "guess" would be that is an issue and needs replacing.

If the property you are looking at has areas where it is deteriorated, that may be an issue, but, overall - it's not a deal breaker in my opinion.

My problem is that the parking areas in front of all the townhomes is deteriorating, and I can't seem to find out if the city will replace the crumbling paving or if each owner is responsible.