It should be done periodically, I think the maint. chart says every two years. You probably won't notice any great improvement, but it's still a good idea to change it. I've seen LR's with 150k on the clock that still have the factory installed filter, not the best way of doing things. Used LR's are famous for lack of any maint., hence the new owners spend a fortune righting these wrongs.

'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S