I've had 2 bikes stolen from me in my lifetime. The first one was chained up and they cut through the chain like it was nothing. The second one was locked in my garage. I was 16 when the first was stolen and maybe 22 for the second. I'm 57 now. What has kept my bikes, and I've always had multiple bikes, safe and secure is that I NEVER LOCK THEM OUTSIDE, ANYWHERE!!! For 30+ years I didn't own a bike lock. A few years ago I decided I wanted to try commuting to work so I bought both the NY Fuhgedaboudit U-Lock, and the top of the line Kryptonite chain lock. I used my old MTB to commute and locked it outside my building within site of the security desk. I got friendly with the security guys so that they'd watch out for me. I used my chain by itself the first year or so and never really used the u-lock. When I was hired by the company after being a consultant for many years, I was allowed to bring the bike inside to the new parking area at the secondary entrance, also under the eyes of security. Now I leave my carbon fiber road bike and use my U-lock. The bike parking feels so secure I didn't lock up my bike once when I forgot my keys. I just made it look like it was locked by looping my helmet around.

As for weight, both of my locks weigh too much to carry and I am leaving them locked to a rack on the street. My laptop weighs enough, I don't need another 10 pounds. I still don't lock my bikes up anywhere else, ever.