EPROMs can store data for a long time, for over 20 years. Depending on the environment and use they start to develop Bit Rot which will eventually corrupt stored data. So pulling the chip and backing up the data is advised.
For those stubborn Eproms I've found it easier to remove the CPU board from the metal tray, use a small flat bladed screw driver to work one end up far enough to permit using a larger wider flat bladed screw driver and work the Eprom out of the socket as evenly as possible from end to end. Yes, avoid making contact with the CPU board surface to reduce the risk of trace damage.
I have experienced Eprom failures but primarily from overvoltage spikes as a result of battery acid damaged traces.