Sale By Owner or Trade-In? Value?

When I sold our last mh several years back, I looked for similar units online and also checked the RV prices on nadaguides.com, using the lowest retail without options to figure an approx value if I sold myself. For trades, after you factor in the difference in sales tax on trade and also an amount of cushion for the "pain in the neck" factor of selling it yourself....you may come up with what would make sense. For example, if you could sell it yourself for $40k but could get $35k on trade, assuming a 7% sales tax rate that $35k is actually worth $37,450 to you. So the question would be, is the remaining difference of $2,550 worth it to you to have it gone and not have to deal with selling it? I know your numbers would be quite different, but that gives you the thought process I went through.