Idiom request for wasting time or money

Consider the colloquial idiom fritter away.

Thus spake dictionary.com:

verb (used with object) 1. to squander or disperse piecemeal; waste little by little (usually followed by away): to fritter away one's money; to fritter away an afternoon. 2. to break or tear into small pieces or shreds. verb (used without object) 3. to dwindle, shrink, degenerate, etc. (often followed by away): to watch one's fortune fritter away.

The lazy student frittered away his time, his parents' money, and his prospects for a prosperous future.

A person who makes bad decisions now and will have to pay for them later can be said to have mortgaged their future. A single word for this would be to squander time or money.