How long does a LIRR Monthly pass last?

Question

Does it last until the month ends, or for 30 days or something?

Answer 1

End of the month. I live in Bayside NYC.

It can suck if you have to go on vacation and such and you've paid for the month.

Answer 2

In Houston, monthly passes work for the given month for a specific zone ( cost ).  There are also value passes which deducts the cost of a trip from your card each time you board.  They are good indefinitely and perfect for those times like when you go on vacation.  You probably have a good idea how much your weekly travel cost is and you plan accordingly by buying the appropriate value pass.