Would you recommend replacing the cast iron drain line since it lasts only 50 years?

However I’m running into the following problems:1.iron cast plumbing.

Common causes are a nearby bbq grill, burning debris or leaves too close to the house, etc.

One remote I got back I thought it was dipped in BBQ sauce. 

I am grateful that I have never had a terrible tenant that does 10-20k in damage on move out, but I have spoken to several people who have (ironically all of these stories come from people that invest OOS).  

The Bible says, Iron sharpens Irons!

Tenants not paying- tenants destroying ur freshly remodeled property- furnace needs replacedgetting sued- plumbing in a fully occupied 4 plex is backed up snake cant get through, house sits on a slab, and u have to dig up concrete in apartment to replace cast iron while u have 4 families screaming at you.

Yes, ironically it's the people who have been successful in real estate for 20-30 years who might be successful in wholesaling.

IRONICALLY my fiancé after spending the last 10 years in the waiting industry just went full time artist!

my houses are old 50's or 60's home,and could have cast iron pipes,who knowns people could get sick because of that and I doubt someone would cover this,the list of eventual issues seems endless to me..My question is how can I sleep at night and take advantage of the great potential of rental investments?