Service after purchase

I have a habit, which I use also for motorcycles, that soon after buying I change motor oil and filters. I think it is good practice because you never know if seller done this when he/she intends to sell a car. So if I do not have a clear confirmation in the form of a bill, I usually do not believe the assurances of the seller and will do a "new opening" that is, replace fluids and filters. I did it a few days after the purchase of Mazda. Full synthetic oil Motul 8100 X-Clean+ SAE 5W30 (6l), DOT 5.1 brake fluid, and appropriate filters (oil and air) I bought from a friend's company from Krakow, and I went to a Mazda Dealership in Katowice to change them.