Well, andresamia, I initially did oil changes every 5000km. That only lasted a few months, because I was changing the oil ever 5-6 weeks. I noticed that the owners manual recommended every 7500km for an oil change interval for severe duty service. I decided that 8000km oil change intervals were easier to keep track of in my head, so I started using that interval. I can now go 8-10 weeks between oil changes. Where I live I'm a long way from anywhere, so any short round-trip puts on at least 150km. Over this past Christmas holiday i put on almost 4000km - all of it on just getting from place to place, no real big trip involved. My engine doesn't use any oil at all, knock on wood. It starts and runs fine. I firmly believe that a vehicle that sits, ages quicker that one that is used all the time. Seals can dry up and wear out, bearings etc. can have the oil eventually flow away, and that creates extra wear when the engine is finally started after sitting for quite a while. Just my opinion.
I've gone through probably 3-4 sets of brake pads (no surprise), and I've changed all of the brake calipers and rotors once. They tend to live in a harsh environment under the car (salt, mud, wet, etc ...). I've changed the rear shocks and front struts once. I changed the manual transmission fluid once, at around 250,000km. There is no service interval for that fluid change. I noticed absolutely no difference in how the transmission shifted after the fluid change, so I probably didn't have to change it. I change the coolant every couple of years or so (about every 100,000km). I changed the spark plugs for the first time at 220,000km myself. I just changed them recently again at 440,000km. Changing them made no difference in how the engine ran or its fuel economy. The center electrode sure was worn down quite a bit compared to the new plugs, but that's it.
One problem I had was with the parking brake cables. The main one going from the handle broke once. And the cable that goes to the right rear brake started to stick and not release, so I had to replace it also. I did replace the right front wheel bearing at only 135,000km. I've replaced both half-shafts a number of times to get new CV joints (they start clicking). It's stupid that it's just as expensive to replace the whole half shaft (both CV joints) as it is to replace just the bad CV joint. I guess the extra spendt on parts is saved in labor costs. The last thing I've had to get fixed in the seal for the left half-shaft where it comes out of the transmission; it started leaking on me. That' it!
This car basically gets driven every day. I don't hesitate to hop in it and go anywhere and at anytime. Other than a spot of rust starting to show around one rear wheel well, all I have are lots of stone chips and parking lot dings/scratches. It's been a very good vehicle. I look forward to hoping in and driving it every time I need to go somewhere. I wish Mazda would make an updated 5 so that when my 5 finally dies, I don't have to buy a larger SUV in order to get 3 rows that seat at least 6 people. Oh well ....
P.S. - it now has 463,000km on it