Laptop has to support booting from USB. Not all do. I hadn't thought of this option, but it could be valid.

>Swapping main HD was something I tried a few years ago - did not sit well with me. Swapping a second HD in a 17' is another case - that worked quite well. Similar in 15' if you opt to work with SSD, HD and external DVD. Another option with most laptops is USB3: if the machine does not support it, an adapter is cheap and the speed are good enough for a multi-GB copy if that is really needed. Often just working with the external disk is good enough. YMMV...