This isn't so much DIY, but I figured it'd be a good pool of people to ask.
My wife and I own a 2BR Condo that we rent out to a great tenant. The condo was built, as far as I know, about 20 years ago and still has the original water heater. The condo association recently sent out a letter to owners stating that some of the original heaters have started to leak, causing damage to units below. They recommended replacement ASAP.
I need to double-check, but as I said I believe ours has one of the original ones. If we do need to replace it, what kind of unit should we be looking to buy? 2BR Condo, single tenant, washer/dryer, dishwasher, tenant pays the gas/electric bill. Unit has gas and electric hookups.