I thought about renting time, but if you do that, you have to finish the quilt in one session -- or -- unpin it and repin it (yuck) -- or -- buy your own leaders. I finally decided that I wanted my own machine so I could leave the quilt on the frame until I was through quilting it. I bought a used HQ Avante with the Prostitcher. I don't regret the decision but wish I had done a little more research as there were several upgrades already out and in the pipeline which I had to purchase later. I've probably spent as much as the cost of a new unit. All that said, I love my Avante and the Prostitcher is the cat's pj's. I have a BAQ on it right now and hopefully, will finish quilting it today. Yes, it does sit idle sometimes while I'm piecing, but I love having it there when I need it.
A comment on quilting for others... I am a very picky piecer. My seams are all pressed flat and my threads are trimmed. When I finish my flimsy, it's ready to go on the frame. I quilted one top for a friend's mother and it took me two days of pressing and trimming to get the top ready to put on the frame. If you quilt for others, you will probably see all kinds of things.