Yes, fluid at a minimum. I replaced bushings (along with fluid &seals) at around 35K miles since the forks had developed a harsh ride. Now it's at 75K miles and riding harsh again so I'll be rebuilding the forks today.
What I've discovered with suspension upgrades after doing more than I care to admit, is if you don't notice a problem you don't need an upgrade. I only found the Elka shock to be slightly better than stock, but every other upgrade was no better, or was worse than stock. I must be the model rider that the OEM's tune their suspension to.
2009 Wee Strom ABS (current)
1987 Harley Low Rider Sport (current with 200K miles)
2009 Aprilia Mana 850, 2006 SV650, 1984 Yamaha Virago 1000 (all sold)
Silver Strom Club Member #11
Wee Farkles in order of importance: Russell Day Long Seat, Madstad with Moose Adventure Shield +4'', SWMotech Centerstand, Givi XS308 Tankbag, Aprilia mirrors, Framesliders, Fenda Extenda, Elka Shock.