While not all batteries are created equal, longevity soley relies on proper maintenance. For example: Using distilled water, not tap water if you have to top off fluids.
The true kiss of death to ANY battery is leaving them uncharged for any length of time. If you properly charge your batteries after every use, even if it is an hour of usage, you should expect several years out of your battery.
“Smart” chargers are the only way to go, meaning your batteries won’t over charge.
The other best advice I can give is to take a multi-meter with you when you purchase a battery. NEVER-EVER-EVER purchase a battery that is lower than 12.7 volts. NEVER! 12.8 volts would be better. A battery that is on the shelf that is below 12.7 volts is losing it’s “full capacity” of charging and sulfation is already building on the lead plates. Once the sulfation starts, it is difficult to reverse it.
If you are unsure of your current battery status, you can perform a simple check at home. After fully charging your batteries, leave them sit for 48 hours OFF the charger, full disconnected to any device/cable/wire. After 48 hours, your batteries have “calmed down” from charging. If your batterie are at the following volts, you’ll know your status:
12.7 – 12.8: Full to advertised amperage level
12.6: 80% of advertised amperage level
12.5: 60% of advertised amperage level
12.4: 40% of advertised amperage level
12.2: 20% of advertised amperage level
12.0: “dead” battery, that has no amp hours.
Keep your batteries fully charged at all times and you’ll never have to replace them unless they internally break.
Lastly, to truly extend battery life, get a “desulfator”
http://www.batterystuff.com/battery-restoration/12-volt/OBD-12.html