Costs $100 per corner to replace any missing concrete markers.  

And if you really want to diversify, invest into multiple replacement properties with the proceeds.

They expect us to replace lightbulbs, won't change furnace filters and we also have lawn maintenance issues with them.

After a couple of years of treading the path to frugality to build this financial runway, I've networked with the greatest people who made this all happen, of course, it took the strength, determination, time, etc to place myself where I am today but, without the mentorship of my two great mentors whom I wish used BiggerPockets so I can mention, I don't believe I would have made it thus far relying on some whimsical dream that this will all pan out accordingly, thank you for everything Greg and Lashawn.In addition, I would like to thank Bigger Pockets for connecting me with the greatest realtor @Stephen Schmitt Who took my dreams and aspirations to the core when we first connected and spoke about my future goals to replace my W2 job for financial freedom. within three months of me deciding to pull the trigger and get pre-approved, we found this killer cash-cow that apprised over purchase price!!! 

It’s easy to switch it up or add to it or replace it if parts or the whole thing gets damaged.

I recommend establishing a reserve fund for major turnover expenses, capital repairs like a roof replacement, etc.

Otherwise, yes you have to either excavate and repair and replace or run a pipe burst through the line, which is usually as expensive as excavating. 

Labor/material are going to be different and need to factor that in4) new roof, new HVAC, new water heater, ac panel, replacing plumbing to PVCThese are very variable, if you are getting this from a licensed guy to do it and unlicensed.. is it a big shop or a local shop doing it, is the GC doing it they will put some money on the top so it will be more money5) framing (creating new bedrooms or baths)I would get all these quoted from a good couple of licensed guys and unlicensed to know your numbers to cents

If separate, do they both need to be replaced?

Be ware of the ones that get compensated on the back end by trying to refer you to replacement property solutions that compensate them.