If you're being at all conservative, and your estimated range is that close to the wire, it doesn't seem unnecessary, especially when the standard usage pattern

If you're being at all conservative, and your estimated range is that close to the wire, it doesn't seem unnecessary, especially when the standard usage pattern with EVs is to plug them in every night. The Model S seems to be doing a much better job of estimating its battery life than any laptop I've ever owned.