A lot people who never worked with an SLR and decide to get one with a couple of lense think that they can change the lense anywhere and any way they want. This is only partially true. In case you change your lense everywhere without thinking about it you are prone to dusting your sensor, and there is nothing more irritating than cleaning it every few weeks. Once there is dust on it you will see the dust in every picture you take. Dust happens, if you use your camera a lot and change your lenses a lot, you have a higher chance that a few flocks of dust, pollen or something else that flies around in the air, will hit your sensor. Once it happend you can only clean it, either by yourself, which I was too scared to do myself, or you can pay someone else about 15-30$ to do it for you, which I decided was cheaper than a new sensor in case I fuck it up.

Practical tips to keep the dust away

1. Change your lenses in a save environment, which means inside of something, weather is is your car, home or just some simply wind protection like your jacket. It will not keep the complete dust away, but you can reduce the danger.

2. Turn your camera down when changing the lense. It protects the opening of your camera and makes it harder for dust to enter it. Changing your lense quickly in this position takes some training and an additional set of hands helps wonders

3. Use a small air blower(no compressed air as it can damage your camera) regularly. Just get the dust out of your camera before it hits the sensor, you don’t have to go into sensor cleaning mode, you just want to reduce the dangers of the dust that is already in your camera, but not on your sensor.