If you are trying to make a living at playing, then you have to be able to make enough to pay for the upkeep and replacement of your instruments. You can't afford to lose money on a gig and if you blow out a harp every gig, then that has to be figured into your price for the gig.
I guess I've been spoiled, but I couldn't gig with an $89 guitar any more than you could gig with a $4 harp.