Do you remember the last time you received a handwritten card from someone? Almost everyone can. In some cases it may have been months but you still remember it because receiving a card with a hand written message is powerful. In many cases you still have the card around. That gives you an idea how powerful a card can be.
When you as a leader, write out the card you not only show appreciation for something one of your employees has done but you send the message that the person is worth the time it took to write out the card in person and, perhaps, even mail it. The key is that it is personal. People like personal. They like it because there is not enough personal contact with people anymore. Text and e mail may be great to convey information but it is a lousy way to show appreciation.
Sending a card shows that you took the time to 1) purchase the card 2) had to think about what to write and 3) deliver the card. That is powerful because it is not a fake gesture. In one organization where I used to work, the General Manager would send out handwritten birthday cards to people. They loved it. They would look forward to getting the birthday card with his note in it even though they knew it was coming. Imagine the impact if someone is not expecting to get a card.
How does this tie into employee retention? A large portion of the workforce does not feel appreciated. A personal card is one way to show that appreciation. It is a small way BUT it is a powerful way. It creates a personal connection that differentiates you from some other nameless, faceless leader who may not acknowledge the contribution their employee makes. That bond might be just enough to keep that employee from considering a move to another organization where the manager is an unknown when they know that you appreciate them. So, get some cards and keep your eyes open for opportunities to genuinely and powerfully show your employees you appreciate what they do for you.