La ambición rompe el saco.
If you do more than you can handle, you will bust.
(Similar Proverb: Don’t spread yourself too thin.)
My informant, who is bilingual, remembers hearing this proverb from her grandmother, who moved to the United States from Cuba in 1976. (My informant’s mother came to the United States at the same time in 1976).
Her grandmother would always say this to her when she was stressed out. Her grandmother meant to remind her of her limitations with her workload, particularly in high school.
My informant noted that these proverbs are said more by her grandmother than her mother, and hardly ever by her own generation.
My informant also has discussed the effect that speaking English has had on her repeating proverbs in Spanish. She remembers them in Spanish, but does not say them in Spanish. She says the English variants more often than not. I asked about the structure of the proverb, the if/then statement, and if it is popular among Spanish proverbs, but my informant did not have an answer for me.