The AC went out and needs to be replaced in my Florida condo within the first month tenants are renting it, complete with 3 visits from HVAC before the new unit is even installed. 

Would it be expected or normal to offer some form of credit to offset the inconvenience? Obviously I feel badly about it, and the tenants are angry. When things like pipes burst, major appliances die, or mold remediation is needed during tenant occupancy, is it just too-bad-so-sad for the renters?

(Please no "should have" judgement - we owned the place for a month with the AC working perfectly leading up to tenants coming in, and we had a formal inspection as part of the purchase process, of course. The system was 7 years old.)

My one concern about doing the "nice" thing is that these are big time problem tenants. In a different post I explain about how they have complained and asked for maintenance non stop, and how they routinely overstep their boundaries by trying to demand orders for things that are landlord decisions. I worry a discount this month will set precedent.