Evicting low life's (not that all renters are low lifes, I'm referring to those renters who specifically are), does not take the amount of time you would think. It takes about 10 to 15 minutes tops. You, with a doberman, and an assistant, with a can of pepper spray can quickly effect and eviction. The process of throwing their belongings in a dumpster takes a little while, but you'll be posting your next vacancy on Craig's list that evening.
Find out what this guy and girl debt/income ratio is. It doesn't matter if their combined income is sufficient to pay what your asking for rent...what matters is how much they owe all around. So can they still pay you rent and pay other debts and live comfortably? Criminal background check is important too.
Once, I had some crap tenants move out and leave all their crap. I had a sub move all the crap out. Turned out all the crap belonged to "rent a bunch of crap center". This created a new problem. Rent a Center told me to bring the crap back, it worked out well in the end, I bought the crap at a discount from rent a bunch of crap center.