How does Lennie contribute to george?

Lennie often gets in to trouble. For example, the pair have to go and look for work on a new ranch because of what happened in Weed, where Lennie was accused of rape. Lennie doesn't mean to do bad things, but he's a 'dum dum' and this often lands him into situations where only George can help him out. George has know Lennie for a long time, and decided to care for him after Lennie's Aunt Clara died. He knows Lennie very well, which is shown when he tells Lennie to go back to the brush if he gets into any trouble.