Stupid question? Why do people sell good properties?

[Caleb Mclamb]

This is going to sound dumb but I truely don't understand. Ive been searching properties and out of hundreds have found 4 in my area that are killer deals, meeting (and exceeding) the 2% rule, while not being in the ghetto or having a cracked foundation. My question is, why would someone sell these investment properties when they cash flow very positively? They already have renters (some of them) and the math shows the owners are collecting a nice check (a check that would definitely cover the mortgage of the property 2 to 3 times over)

Any feedback would be much appreciated, constructive criticism welcome!!