As long as you turn the hot dog warmer down to the low setting after cooking or warming the hot dogs the hot dogs can stay in the hot dog warmer all day without a problem while you eat them.
I make a lot of hot dogs when serving some family when they come around for a get together or party and I keep the hot dogs going on the hot dog warmer all day until they're all gone.
I sometimes keep some hot dogs on the hot dog warmer all day even when it's just me and my husband and kids and we eat the hot dogs throughout the day.
The hot dog warmer helps to keep the hot dogs at a safe temperature to prevent any bacteria growth so it's safe to keep the hot dogs in the hot dog warmer for a whole day and they will not overcook either as long as you turn the hot dog warmer down to the lower setting to just keep the hot dog warmer warming the hot dogs.