Piracy: ꜱᴀɪʟ ᴛʜᴇ ʜɪɢʜ ꜱᴇᴀꜱ

Seeding uses your drive (reads it so long as it's seeding to someone), your bandwidth (obviously), and a negligible amount of power/computational resources.

If you have a tracker you trust you could start by reading their guides. Like my most used public tracker tells you to have a ratio of 0.3, meaning for every part downloaded you seed 0.3 back to the people. I usually stay for at least 1-1.2 until I turn my pc off. If you want to be helpful you could also get some "rare" stuff to seed, same tracker classifies it as having fewer than 5 others seeding it.

In general, "don't hit and run" holds true, if you can seed for just an hour after you've downloaded your stuff, do it. When it comes to torrenting, we are all we got.