Something that lasts for a short time is called temporary or ephemeral.
it lasts forever and ever and ever
Chronic
Everlasting
A long term cause is something that lasts a longer time and a short term cause is something that lasts a shorter time.
He is reported to have said: "The sadness lasts for ever."
as long as it lasts, without going mouldy
It lasts about an hour and something minutes... (no less than 30)
James Jordan has written: 'Forsaken' 'Something that lasts'
Duration is the amount of time something lasts or continues.
Nothing lasts forever. But it's not going anywhere any time soon.
For some considerable time yet, but nothing lasts for ever.