I get this question a lot actually "How often should I get my family photos taken?" There's a few different factors to take into consideration:

1. Kids Ages: I feel like for kid ages 5 and under you really should get photos done every year. Think about how much your kids change every 6 months in those early years. While we are taking cell phone photos every hour, the moments aren't really getting captured. Especially the ones with you in them.
2. Finances: I get that family photos can be pricey so if it's a matter of budgeting, spacing out sessions every few years may be the best way to go. Mini sessions in the fall in the meantime mean you get a Christmas card photo or updated shots of the kids. If there is a photographer you are dreaming of shooting with but can't afford, ask about a payment plan! Most will allow you to make payments as you can up until your session.
3. Milestones: As your kids grow up you may feel like certain seasons need to be documented more. Many of my clients with older kids are waiting every few years to do full sessions, but when they do it's for an upcoming graduation, or a move. Don't wait until it's too late to grab those moments!

Case in point! This family has been getting photos taken by me for the last 3 years in a row! I think you can totally see them change and grow, but still each session is totally unique.