[Speedslug]

How long a tank lasts is going to depend on lots of things.

How big your torch is and how hot you run it are just two factors.

Soft glass is going to less heat to work with than boro.

Are you making beads as big as your finger or objects the size of golf balls or tennis balls?

Do you have the experience and the stamina to work with a monster torch 8 or 12 hours a day and does your lifestyle allow you that much time.

There are some that talk about getting the 5 foot tanks ( I think they are called "K" tanks) swapped out every two weeks and often they complain that they have to go spend the whole day torching because the tank supplier is coming the next day and they need to use up what they have they because they already paid for the gas in it and if it goes back with a quarter tank of oxygen still in it then they will have wasted that money.