Suspension - forks, shocks, stems and so forth (but not seat posts, they have their own thread)

Where is best to get my lefty serviced, how do I know if it needs servicing??

TF tuned

If you are feeling brave, open the top up (you'll need a special tool) then pour out the oil. If there is no oil, or the oil is 'horrible, it needs a service (or is fucked).