Birthday Numbers Are Everywhere

In numerology, it is understood that certain numbers attract certain energies. That can include attention.

Most likely the reason you're seeing your birthday numbers is because you're familiar with them. They have meaning for you.

Many, many numbers are seen. Every day. Few are remembered.

Seeing numbers with personal meaning or with emotional significance attract attention and tend to be remembered.

As you noted, the number 5 with the number 29 are your birthday numbers. They're personal and yours. The day you were born. When they are in your environment together, as number 529, you notice them and remember seeing them.

Because a person remembers seeing those particular numbers and doesn't remember seeing all the other numbers, the ones that have been forgotten, it seems very much like those numbers are the only ones being seen, as if they're making a special effort to be noticed.

When a person starts wondering if there's a hidden message or if the Universe is trying to tell them something, at that point a mystery is created in the person's subconscious.

Mysteries come with a compulsion to be solved. The person's conscious attention will be attracted to the subject of the mystery (the birthday numbers, in this case) whenever available.

Thus, the person starts to see the numbers more often than before. And, most likely, becomes even more convinced that there must be a personal message and, deepening the mystery, with a stronger compulsion to solve it.

Your destiny number is the master number 11. Both your current pinnacle cycle number and your current life period cycle number area also the master number 11.

It is understandable that there is a desire to comprehend the spiritual meanings of things. It this instance, perhaps, it is simply you recognizing the personal numbers composing your day of birth and remembering that you did see them.