If they are aluminum props, go ahead and get a new one, and get the current one repaired for a spare.
Your prop is out of balance. That's the worst thing right now. There's no 'set' way of telling how long you can run it before damaging the lower gear unit.
I think you'll soon discover the price of reparing an SS prop, rather than continuosly buying new aluminum props will more than pay for itself in a season or two.