Be the change you want to see in the world. Don't let your memes stay dreams.

A "planet parade" doesn't have to be the same planets or same configuration each time. The parade can also be as small as 3 planets. So a parade happens when at least 3 of the 8 planets line up. That's not very uncommon.

However,
This planetary parade has 5 planets in it and that does make it notable and uncommon. The last one like it was in 2002 and the next one is expected in 2040, https://starwalk.space/en/news/what-is-planet-parade