I don't know the rationality behind it, and I do it to her as well all the time, though I have been mindful of it and trying to improve.

If it's the latter, well, you can't really rationalize that.

Tax advantages are one of the few rationalizations left for buying at today's low cap rates. 

If you offer $510k for a home and ask for a $10k seller credit, a rational seller advised by their agent will simply view it as "really" a $500k offer.

Try to house hack a triplex or four plex using FHA financing, max out your seller's concessions and rent pro-rations should get you as minimal of a down payment as possible!

Tenants will stay or go regardless of the lease but with M2M the landlord controls if they must go.A term lease assumes a tenant will be good, that is not rational and counter to good business planning.

Simply follow a rational process.

Go to Zillow and type in a search of other like properties in the same area (within 1 mile radius...and in the SAME CITY) and within 10% above/below the as your property's sq ftg...within the last 6 months to get your property value....and no rationalization of that number if you don't like what it says.The market dictates the value of the property...the current market, as in current sales comps...and really nothing else does.  

Then at the closing the tax free cash from the primary residence allocation goes to you and the remaining proceeds go into your 1031 exchange.There is no fixed formula other than that it must be rational and make sense.  

posters are spewing political opinions disguised as rational economic discourse.