replace battery on 2015 Macbook air

In 2016 I got the early 2015 MacBook Air, 8 GB, 256 SSD, i5 I think. It still seems like a great computer to me. However, the battery life is not what it used to be. I haven’t timed it, but I think I only get an hour or two of solid use from a full charge. I cannot afford to buy a new Mac, so I’m thinking about having the battery replaced. Is there anything I should know about having this done, or is there any reason why I should not have it done or why it would not be a good idea?