I started another thread asking if anybody knows where I can get those old Norco or WorldFamous handlebar bags that were so prevalent 30 years ago. I got trolled instead.

I have a 35year old 10 speed racer. I changed the drop handles to straight handlebars. I wear my light on my helmet.

What I found about modern handlebar bags is:

1) I really don't like threading those straps in the cold and the dark. If you have a lot of heavy stuff in it, it's a little more difficult threading the first strap. Those bags of 30 years ago had a metal frame and it was much easier to secure onto the handlebar;

2) you have to raise your handlebar high so that the bag won't rub against the front tire - unless you have fenders;
3) don't pull the straps too tightly against the handlebar or you might inadvertently be tightening your brake cables;
4) it's nice to have extra space to carry more stuff, like tools or foul-weather clothing but it's not only extra weight it's extra wind resistance. I do feel the difference when I repack all that stuff into my trunk to carry not two bags but only one. More bags to take off, more bags to carry around when you lock up your bike.