I’ve been tracking my mental energy for \~2 months. Every day, without fail, I crash around 3pm. It feels like my brain literally runs on a 6-hour battery. I’m now building **TenaQ** — an iOS app that measures your “mental battery” so you can see when you’re actually productive vs when you’re just going through the motions. This isn’t another habit tracker or pomodoro timer. It’s dead simple: * Quick daily check-in (1–10 energy level) * Log what tasks felt easy/medium/hard * App calculates a “willpower score” and shows your strongest hours The concept already got 500+ upvotes on r/productivity, but I’d love some brutal feedback from this crowd before I push to TestFlight. Specifically: 1. Is the value prop clear from the landing page? 2. What would stop you from signing up? 3. Pricing thoughts? (leaning premium: $15/mo or $150/yr) Landing page (rough draft): [tenaq.app](http://tenaq.app)