Remember: those are really custom cards, so you can easily transform any free ecard in a free birthday card, for instance. Most of them are animated flash ecards too. Explore your creativity and enjoy Birthday cards for best friends!
- When the most significant digit changes, for example one's 1st, 10th, 20th, 50th, or 100th birthdays.
- In most legal systems, one becomes a legal adult on a particular birthday, and at different ages gain different rights and responsibilities -- voting, eligibility for military draft, etc.