Loud is right here, that battery looks rather old and they for sure have a limited lifespan based on usage and maintenance. Basically any battery should hold up for at least a year if kept charged and used properly. Good batteries should last at least 5 years under the same conditions. The best batteries in the world will hold up for maybe 10 years. But be sure that an older battery has for sure lost a good portion of it's lifespan. You should be paying a mere fraction of new cost for an old battery.
Think of it as pizza. You are buying left over pizza from last week out of some dudes nasty fridge and there is only 2 slices left. He is asking full price of a whole pizza. Are you buying?