What's your opinion on time limits for Dope polls?

Many Dope polls have voting open for extremely short periods. How better to explain why, than with another poll?

I usually do mine for 1 year, if you want to know.

a poll asking for data at that time; what is your age or who would you vote for next week should have a short period to keep the data meaningful.

have you ever eaten Chinese food could stay open longer.