Originally Posted by
Gyrine
2) I use a bivy bag because it is much warmer than a tent, lighter than a tent, and also takes up little room in your ruck - less than my sleeping bag. The bivy adds to the overall warmth much more than a tent because of the smaller space. And it keeps the down bag dry. Lastly, if it is a warm night, forget the sleeping bag and just slide into the bivy. The only advantage of a tent is if you are using it for more than one person - and you get the other guy to carry it.
Many bivies are heavier than the single walled ultralight tents that you can get today, but the bid issue I have with a bivy is condensation. At least in a single walled tent the condensations is kept well away from the sleeping bag. The few times that I've slept in a bivy my bag as ended up damp.