If you use your laptop 24/7 and leave it always running then yeah even in a clean environment this would make sense.

I use my laptop occasionally over a few years and there was almost no dust in my fans.

It’s important to vacuum your living space frequently and keep your laptop on a desk. If you have pets, they exponentially increase dust intake. Having this level of dust in one year just points at a high level of dust environment.

I would clean it every 3 months if this is what you gathered over a year. You lost a lot of performance and efficiency overtime, you will gain it back once it’s cleaned though.