Advantages of metal vs glass stockpot lids I just ordered a new 6 qt stockpot (that I use for soups and stews) and it came with a metal lid.  All the stockpots I owned before had glass lids with a small vent hole to release some steam.

An obvious advantage of glass lids is that you can see the food being cooked and monitor the level of boiling.  Are there any advantages of metal lids?  E.g. do they keep more heat inside if you keep it on vs letting heat out?
They don't break if you drop it on the floor. That about covers the advantages of a metal lid here.

The "heat kept in" is largely a matter of the steam condensing on the lid, and is pretty much exactly the same for metal or glass lids, or a sheet of tinfoil over the pot. If they are on, it is, if they are off, it's not.