As a leader, you often decide when someone is ready for a promotion or given one.
Promotions are essential for the career growth of your team. If you don't have a solid cultural balance of promoting existing people and giving them new opportunities, you will lose your best team members.
With a bit of a mindset shift in how you promote, you can maximize the benefits to both you and the team member.
The prevalent way to promote people is to dangle the carrot on the stick
— "you do X, and you'll get Y." This is extrinsic motivation, and I don't believe this is the best approach to promoting people.
I prefer intrinsic motivation as much as possible, where people motivate themselves for the fun and challenge of the work itself.
This type of motivation doesn't rely on rewards for sustainment and can be sustained over long periods.
One way you can do this is by giving people a reputation to live up to.
This means taking bets on people, backing them and promoting them before they are fully ready, mentoring and training them, and giving them the opportunities they want but have never had.
There is nothing more motivating for a team member than being given a great new opportunity, having something to prove, and knowing that you also completely have their back in support.