What's the best mortgage length you all do?

[Dylan Burnett]

A teacher I used to have has 38 properties and all 10/15 year mortgages which all have break even cash flow which in turn lowers his taxes from his full time job. After the 10/15 years he refinances and pulls out as much as he can from the properties which he puts Into retirement accounts plus all of the money is untaxed . What do you all think of this and if anyone has another strategy I would like to hear about it