A good burning barrel needs holes near the bottom to supply air. A pick axe or a geology hammer works well for putting in the holes. Put most of them between 6 and 12 inches from the base.
Used for burning trash on a weekly basis a barrel lasts for years. If you store it where it is dry, it will last longer, as the alternation of heat and wet causes it to rust faster.
Leave a few inches of ashes in it when emptying. This protects the bottom from the heat of the coals.
If you store it out of the weather during the off season it will last longer. failing that, store it upside down. This will slow down the bottom rusting out.