Definition & Meaning of "[have] a (memory|mind|head|brain) like a sieve"

What is the origin of the idiom "have a memory like a sieve" and when to use it?

The idiom "have a memory like a sieve" likely draws its comparison from a sieve, a kitchen tool used to strain liquids or separate particles, which has many holes or openings. Just as a sieve allows small particles to pass through and be lost, someone described as having a "memory like a sieve" is thought to forget things easily or have trouble retaining information. This expression is used to humorously or critically describe someone who has a poor memory or frequently forgets things. It suggests that their memory is unreliable, much like a sieve that allows things to slip through.