It would be smart if the length of the word was directly proportional to the duration of the link. 5-minute links might be more likely to get a 5-letter word,

It would be smart if the length of the word was directly proportional to the duration of the link. 5-minute links might be more likely to get a 5-letter word, whereas a 24 hour link might be more likely to be a 10-12 letter word. Otherwise, why would I not always choose to make my link persist for 24 hours?