> 2. Short lived + well-defined lifetime (per frame/request). Can be allocated in a memory arena. You now have an "arena management" problem. Figuring out the

> 2. Short lived + well-defined lifetime (per frame/request). Can be allocated in a memory arena. You now have an "arena management" problem. Figuring out the correct arena to allocate from can be a problem. (You want to put all objects that become unused at the same time into the same arena, but that's not the same as all temporary objects allocated between time t and t+delta.)