Surprisingly saunas do not require that much maintenance. However there are a few things you need to be aware of when taking care of it. The level of maintenance varies slightly depending on the sauna.
The traditional sauna requires more maintenance than the infrared sauna, purely because it has little bit extra involved in it. Smoke saunas on the other hand require much more time and maintenance, which is why they are not as popular. Electric heaters which are installed in most saunas these days require almost no maintenance
In a traditional sauna if you are heating stones eventually those stones can crack and break down. The other factor is the heat. Because traditional saunas get extremely hot this can cause your sauna door to swell, which means you might end up making adjustments over time.
When cleaning your sauna do not use cleaning agents as this can release toxins in the air when the sauna heats up. Never use ammonia based cleaners they can cause the wood to turn gray. The wood in your sauna can be made of a wood such as spruce. When purchasing your sauna it is advised to ask the sauna supplier how best to maintain the wood, especially since this may vary from manufacturer to manufacturer.
With very minimal maintenance you can keep your sauna room looking great. The only actual maintenance you will need to do is to wipe down the walls and benches frequently with a mild solution of water and soap, this way you can make sure your sauna always looks its best.