Asphalt Legends Unite

There are three ways to gain "garage XP":

1. Upgrade a stage on a car
2. Unlock a car
3. Star up a car

Each time you unlock or star up a car, you'll see in the lower right corner how much garage XP you've been awarded. You won't see this amount when you upgrade car stages, but it also gives you small amounts each time.

Since you have to upgrade stages on cars to win races, and you have to unlock 30 cars and star up 30 cars for other achievements, this achievement is unavoidable as you unlock those. The max garage level is Level 8, and you can expect to be Level 7 or 8 by the time you're done with everything else.