Flamestrike
Legend
That seems rather extreme to me.
How so?
That's a long rest every 12 hours of play (4 x 3 hour sessions). That sounds about right to me, with time for 1-2 combat encounters per session (so around 4-8 combats per long rest).
Where so many DMs screw up is they conflate 'adventuring day' with 'game session'.
Not that there is anything wrong with 'auto rest on end of session'. But if you're not getting more than 2-3 encounters in per session, it should be auto SHORT rest at the end of the session, with every third such end of session rest being a Long rest.