felix--you're right that the network prefers those with high uptimes, rather than those who just jump on and off the network.

Your ISP should have a "usage" page for your account, so check with the help desk on getting access to it. Mine usually updates a day later, but it's still better than relying on LW's options->statistics->bandwidth.

The ISP data is the best way to monitor your bandwidth, since that's what they would use to decide if you are exceeding their monthly 'limits.'

Once you can see the patterns, you'll be able to adjust your shares/upload slots accordingly

I don't know what the ISPs are like anywhere else but here in Australia they're too expensive especially when it comes to broadband connections.
They charge too much and their download limits are too low, some as low as 400mb per month so we simply cannot stay connected to LimeWire indefinitely otherwise we either get choked back to lower than dialup speeds or are charged extra fees in excess of 15cents per mb.
Believe me, we entertain the belief that information should be free to pass on to others but the greed of some corporations puts a price on it whether we like it or not.