Cast iron pipe replacement for a SFH built in 1979

[Jason Sung]

For a SFH in Plano TX built in 1979 in recently purchased, it had foundation issue and plumbing issue. I fixed the foundation and now I am trying to fix the plumbing issue.

One bathroom in the living room is right on the spot with the foundation issue and it appears that it has not been used for long time. 

Would you recommend replacing the cast iron drain line since it lasts only 50 years? Or, should I just find the spots with issues and fix them? 

FYI, tThe house does not have cleanout and the cost estimate for installing cleanout is ~$1600. 

[Andy Sabisch]

What is driving you to replace the drain line?  I have had homes much older than 1979 with cast iron pipes and as long as the slope is correct, they last a lot longer than 50 years.  We did one recently that was a 1970's build where the drain from the kitchen sink was incorrect and it had water in it all the time - it separated when we pulled the sink causing us to pull the wall apart to repair but the slope was not correct.

Do you have a slab or basement / crawl space that allows you to easily get to the plumbing?  Hate to see you tear up a slab if there is no issue.  Even if it has not been used for some time, do you know if there is a drain issue?  I would look at running a camera down the drain line to see if there is anything to be concerned about before jumping into major repairs.