In other words, are 3 bedroom houses selling for the same as 4 bedrooms, or if you are doing a rehab, do you really need to add that extra 200sf of gla, or do you install solid surface counters (Silestone, Quartz, etc), or can you get the same reaction with granite counters, etc.

Make sure the condition of the current surface is considered in all your quotes, that is why people say to get estimates. 

This makes them *at least* 45-50 years old, and frequently near their end of life 70 - 90 years old.On the waste side, the spalling and rust on the inside of the pipe creates a rough surface and constrictions which lead to easily plugged drains.  

Here are some questions:Does hardwood floor surfacing "depreciate" like carpet?

Converting SFH to duplexes is much more difficult to do well than it appears on the surface.

I know many people personally who have all the surface appearances like homes, cars, new granite stainless steel kitchens who are all neck deep in debt.

If the surface is raised more than 1 inch difference between sections,, then it's a trip hazzard and they would replace the entire section, or cut out I will say if the city does the work they contract with cement guys and they do it at a better price than what you could probably do yourself. 

Something designed to encapsulate fire damaged materials is ideal.On concrete, hire in a professional power washing or steam cleaning company with a vacuum recovery surface cleaning system...or see if a steam carpet cleaning company would be willing to do the concrete.

Thus, allowing for proper pitch and grade as well as making for a surface that will never need to be replaced in the future.

Should I just charge them for the re-surfacing?