Fixer, Fundamental Question

[dufffader]

I never seem to ever exhaust my fixer (Ilford Rapid Fixer). Chances are I'll dump the fixer after a month or two when it starts to stink up my darkroom (actually my bathroom) after going through about 20ish rolls. Mine goes gets flushed down the toilet, not sure the environment friendliness of that. It will still fix the film leader test strip in 3 mins of less though.