Hard to say without knowing details.
For example, 10 months deployment and a year of maintenance life suits me for many ships that are supposed to be capable of extended operations. Maintenance is a little longer because having something blow up is more embarrassing than having a cranky crew, and because I'd like to have a reserve for repairs if I get into a fight at the end of an extended mission.
But if you have many frontier populations while only your homeworld has maintenance facilities, your frontier patrol may want ships that have years of maintenance life but only a month of deployment time or so.
And sometimes it's not a question what you need, but what you can get cheaply. An AMM base using box launchers requires very little crew and engineering spaces to have a mission life of years to decades. The option to dump them anywhere and forget about them is nice to have even if you don't intend to do so.