Seeding is an interesting issue, and there are no hard, fast rules.
In FrostWire, you can see upload/download ratio in the transfer window.
Right button the title line and select what you want to see.
I have everything but started on checked. Everything there can be useful.
Some files have hundreds of seeds, and unless you have fantastic line speed, your contribution may not be needed. Other torrents are almost orphan, and you can provide a real service by seeding those. There are no ratio rules on FrostWire files. Let your conscience be your guide. It's good to give more than you get, thus allowing the swarm to grow, but sometimes that's just not practical. Bandwidth is a finite resource!
It's a gut call. I have torrents that I really like, and I seed them most of the time. Popular items, with a gazillion seeds, I cancel rather quickly. I only have so much band width to spare, so I try to use it wisely.
It's a gut call!