Crack the code!

Picture yourself in this scenario: there's a door that's locked, but you want to get through because you heard there was a treasure trove of baked goods behind that door.

There's one way through: A key code combination, where the answer is a 4 Digit number. It's easy to guess the numbers used due to their being worn out: 1, 3, 7 and 9. But what order do they go in?

Also, you have 3 tries before the whole system locks down, preventing you from getting the delicious treats. And destroying the door is impossible, it's made of the toughest substance known to man.

What is the combination?

 

Nope! None are right! You're best thinking about what sort of code would be used: Is there some sort of hidden meaning in the code? Could the number apply elsewhere?

 

Well, the most obvious wearing down is the number 1, but the rest look similar in wear. So we know the most likely first number is 1.

 

Wow, that's actually a really clever deduction @[member="8-Bit-Eevee"], but unfortunately just coincidental. You're getting closer though, because (apart from 1) you got one of the numbers right! Think, what could possibly be linked to this number code? Maybe it could relate to the person in a personal manner...

 

You've cracked it (Much goodies you'll have!)
It wasn't actually based off that, it was based on the idea of using a birth date for the code, for easy remembrance. If the code relates to something personal, one thing it could be is their year of birth, thus making something that's harder to forget!

Now I have to think of a new code...

All right! A new door has been found, and much like the previous one, there are numbers with obvious wear. The numbers are 1, 4, 5, 7... And 9. Clearly, a number is here as a trick. What's the code, and what number is the trick? You get 3 tries, like last time.