You are a healthcare and email marketing expert. Write a detailed, 2500-word guide on email for chiropractors. The guide must cover: 1) Building an email list of patients, 2) Welcome sequences for new patients, 3) Appointment confirmations and reminders, 4) Educational content and wellness tips, 5) Promotional emails for services, 6) Seasonal and holiday campaigns, 7) Patient appreciation and birthday offers, 8) Referral request emails, 9) Re-engagement for inactive patients, 10) Metrics for chiropractors (appointments).