A few ideas on Trojans T105 and T105RE’s.
Yes, they can last 7-10 years if they are not discharged more than 20% i.e. lightly used daily, as then their cycle rate is 4000 i.e. 10 years.
At 50% discharge – basically flat – they have 1600 cycles, about 4.5 years.
It is good to only lightly discharge batteries. One can push them now and then to 50% just to stir their juices a bit as batteries standing lightly used can die earlier due to sediments inside them not being “moved” – used hard / equalized.
Keep them watered, distilled water only(!), push them a bit once a month, every 2 months, equalize them once or twice year. I shake mine, as they are in a wooden box on wheels. I also swap the batteries where the positive and negative cables are connected to, with ones inside twice a year.
Always feel their temperature by hand, pole, side, top, or a fish tank thermometer per battery. If a battery starts heating up, it is busy dying.
If there are a few batteries in a bank connected series / parallel, it is a good ideas to monitor the difference in voltages between the batteries. As with temp, another good indicator that a battery is slowly dying. One can buy battery balancers to help with that.