Hi Limmer- the key for battery
longevity is to not let the battery
bank become less than 50% discharged. 10.5 volts is discharged.... I'm sure that someone will chime in soon with the voltage for 50% discharge.
You may want to consider eventually installing a battery bank monitor
that will let you know when the batteries are 50% discharged... ours reads in amp-hours used and % capacity remaining. There are several options/manufacturers for the monitors.
For capacity and longevity, we ditched the 2-bank house system and wired for one large battery bank, plus a separate/isolated starting battery. This allows us more amp-hour capacity for house loads while reducing the depth
of discharge on house bank.