According to Osho, action without attachment is both sadhana and siddhi: at first it is a practiced remembrance—frequently lost and regained; when ripened, it flowers as effortless non-attachment. The test is simple: if you must remember to be unattached, it is practice; when non-attachment happens by itself in all situations, it is attainment.
It’s like learning to ride a bike: first you keep reminding yourself to balance, later you just ride without thinking.