I have a 2000 Protege LX with an automatic transmission, and I must admit that it is a great car. I bought it in 2001 with only 12,050 miles, and since then, I have religiously serviced the car in accordance to its recommended maintenance schedule.
I changed the oil every 3,000-4,000 miles, minor and major tune ups at 15K and 30K mile intervals to date; included a timing belt, water pump, radiator, transmission service and new brake pads every 17k or so (rear brake shoes replaced only once at 92K).
The 'check engine light' came on at 38k miles, and the 'Air Flow Meter' sensor was replaced under warranty from the dealer. The light stayed "off" ever since.
Recently, I've noticed that the car was running kind of underpowered and a bit sluggish. It also revs kind of high off the line, and would occasionally 'jerk' while I'm driving at a steady speed, whether fast or slow (like the transmission is slipping, or a sudden drop in acceleration).
I've noticed when I was tuning up the car while replacing the air filter, the 'Air Intake Hose' had some cracks along its ridges, and I knew right away that was the culprit. I temporarily wrapped it up with fiber tape and immediately noticed a difference in power and acceleration. Today, I went down to the Mazda dealer and purchased the intake hose and replaced it myself; it's a 15-minute job, and it made all the difference in the world in terms of pick-up and power. I enjoy driving my Protege even more now.
Word of advice: I have been reading a lot of posts here, and I must say that servicing your car at a timely manner within its recommended schedule, is key to prolonging your car. This will indeed help eliminate all sorts of problems in the long run (minor and major), including the financial part.
By the way, my mechanic said I didn't have to change the regular belts. I've yet to change it since I bought the car. They checked it and I checked it also, and it is still tight and strong... even at 110k currently. I wonder when I'll need them. Will replace on my next tune-up at around 125,000. Cross my fingers!