How many years to finance a conventional mortgage

[Kyle Lane]

I'm going to start by apologizing if I have posted my question in the wrong spot. I have entered into a partnership with a local investor in my hometown. He advises me against financing deals that can't be paid off within 10-15 years. I found a 12 unit apartment that could feasibly cash flow 1k-1.2k per month with a 20 year note and 20% down. I came to this conclusion using the BP analysis tool. I have to do more research on the deal but I think it's defiantly worth looking into. If someone could please point me to some insight on what would make a good or bad deal based on amortization periods I would appreciate it thank you.