how long do you guys..

how long do you guys on here lift weights? i just started getting into lifting.. setting aside cardio a couple days a week to lift.. i just use to elliptical 10 mins when i lift weights.. normally i got for 30-60 minutes. i lifted for roughly 30 minutes today. just wondering how long is long enough to lift weights for the day? i worked mainly on my legs. i have 8 pound weights and a resistance band at home for my arms.