How much importance do you place on meta description?
If you have an old site, this is probably a moot point. You are probably ignoring it and letting the pre-existing meta descriptions linger as they always have been. But what if you were handed a 1000 page site? Would you take the time to craft meta descriptions for all the pages? Or only for the top pages (& how would you define a top page)?
Instead of writing 1000 meta descriptions, you could probably craft several good articles. When time & budget is limited where do you prefer to draw the line between meta descriptions & focusing on the visible content for your users?