Arrived to the home, customer had renovtheir master bathroom two years ago and had an Amazon shower tower installed. Only till recently have they had issues with running out of hot water. I am familiar with these shower systems, most are not American made and have no flow restrictions. By plumbing code, no fixture in a home can not exceed 2.5 gallons per minute. This system provides water at whatever the homes pressure is. Client had stated that it worked fine since the install by only recently have they experienced issues with running out of hot water. I next made it to the water heater, I discovered that the existing 75 gallon water heater is 14yrs old, has signs of wear and tear and rust on the jacket of the tank as well. I also discovered that the gas valve is cranked up to its hottest setting and the hot side pipe is not very hot. To be proactive, I advised to the client that replacement of the water heater is recommended due to its age, also that this issue just started happening