I like to shoot for 10 minutes total by doing 10 x 1 minute intervals. Longer than 1 minute gets boring. I am a big fan of condensing workouts when possible, so I would do a set of bench, for example, then 1 minute of jump rope, then bench again.
Also, You can mess around with the 1 minute. For example, sometime I do 1 minute at a regular pace, or sometimes I do a 10 second burst of really fast jump roping, 20 seconds normal, 10 second burst and 20 seconds normal for 1 minute of jump roping.
Hope that helps. I love it, it is my favorite form of cardio (aside from playing a game of basketball or soccer with friends) and you can do it anywhere.
James 1:16-17 ESV
Do not be deceived, my beloved brothers. Every good gift and every perfect gift is from above, coming down from the Father of lights
With God's help...Mens sana in corpore sano