There is no one size fits all answer. Where I started was finding out which rewards programs I wanted to be able to transfer to. Different cards earn points and transfer out at different rates, so some will be more useful to you than others. Once you start to narrow down the options, you can decide on whether you’ll get real value out of the annual fee, and take into account any signup bonus year one. Take your time to learn about your options, as for many of us earning enough points for a reward flight requires years of careful planning and hard spend. You don’t want to get locked into one program and realise later that you are never going to get value from it. Signing up for the beginner email course on this site is also really helpful.