Star Wars: 10 Things You Didn't Know About R2-D2
5. There's A Reason R2-D2 Stopped Using His Rocket Boosters
Being used primarily as general-purpose ship mechanics, astromechs often have to operate in hard-to-reach places, or even outside in the vacuum of space. To help with this they're fitted with rocket boosters that let them fly around.
As a big hero during the Clone Wars, R2-D2 used his rockets frequently, even using them to carry people to safety, once rescuing Chancellor Palpatine this way, and taking down two super battle droids in Revenge of the Sith. Sometime after the war he steps using them, and we never see him use the feature in the original Star Wars trilogy, even though they'd have come in handy several times.
You might think that there was a heroic reason for this, and a good story to go with it, but it's actually quite mundane, and comes down to the company that made R2 himself.
By the time of A New Hope, he's well over 30 years old, and his warranty is long out of date, so when his boosters break, they can't be replaced. It seems that Industrial Automaton doesn't offer a spare parts service either. While this must hamper his abilities to perform repairs, it doesn't stop him playing the hero, and being even more daring as a member of the Rebellion.