For how long does sangria last?

Assuming that you're talking about a sangria that has been made with fresh fruit, and not a shelf-stable product, it will last for about 3-4 days in the refrigerator. After that, the fruit will start to break down and the sangria will end up being less tasty.  https://geogenes.org/?p=291 You can freeze the fruit prior to including it to the red wine if you're looking to extend the life of your sangria. This will assist to keep the fruit fresh and the sangria tasty for a longer time period.