Three bookings to make before anything else
In order of urgency: Alhambra Nasrid Palaces slot (2–3 months ahead in peak season), Sacromonte flamenco cave show (2–4 weeks ahead, specific venues sell out faster), car rental for Day 5 if you are doing Guadix or the Alpujarras (1 week is usually fine outside August). Everything else on a 5-day trip — the hammam, the Cathedral, Bañuelo, Cartuja — is walk-up or same-day bookable.