See how the cast of 'Happy Days' changed from their first to last episodes

A lot can change over the course of 11 years.

When Happy Days premiered in 1974, no one could have predicted its success. The hit sitcom sat atop the ratings, generated a few popular catchphrases, and spawned two massive spin-offs in the 1970s (not to mention some less successful ones). 

Of course, such a long run meant some substantial changes. Main characters left the series, new ones were added, and sharks were jumped along the way. Airing a decade apart, the first and last episodes of the series could easily be two separate television shows. 

Here's a look at how some of the characters — even a minor one — changed from their first episode of the show to their last one. It's amazing how 11 seasons will change you.

Richie Cunningham 

Joannie Cunningham 

Marion Cunningham 

Howard Cunningham 

Potsie Weber 

Ralph Malph 

Arthur "Fonzie" Fonzarelli 

Chachi Arcola 

And finally... Chuck Cunningham (Gavan O'Herlihy)