Vacation house - only there on weekends. AC wouldn't blow cold, so called repair. He came on Sunday, checked pressure from outside, said we have a leak, probably coil inside. Didn't have time that day to repair, but recharged with some refrigerant and made appt to come back to check during week while we not there.

During the week he said he did test and sniffer detected a leak at inside coil. Estimated $970 in parts and labor for new coil + Sunday call to recharge. Say OK and make appt for Monday repair, since he says charge should still hold us over weekend.

Thursday night we show up and house won't cool at all - called repair and told him we can't make it throuh weekend you need to do something. He came out and no pressure at all "at the head". He tried to re-charge and we can hear a large leak outside. He solders this "new leak" and fixes this - and then we go inside to check the coil. His sniffer does detect some leakage - but in a very specific spot and not 100% of the time he hold the device in this spot. He says he still strongly recomends we replace coil.

My question is "does the sniffer going off mean for 100% this is a leak that we should get fixed"? Or is it possible this outside leak could be the real reason for our AC problems? Will this need to be fixed eventually for sure? Are very small leaks inside like this common?

Any advice?

Just not sure if still makes sense to spend the $970 but don't know if this outside leak is relevant?