I bought a multicolor set of staedtler triplus fine liners and I use them almost exclusively for spirographs. Does anyone else use these, and if so, have you found that the ones you use most run out of ink in a couple months? I've seen staedtler fine liners recommended for this purpose so I didn't expect to run into this problem so soon. I do use them heavily though so I'm wondering if I've been extra hard on them.
Anyone have any better recommendations for this type of pen? Or should I just expect to go through them rather quickly?