Some people might question why I format the numbers the way I do. Well, the rationale is to bring it as close to the ITU standards when formatting. I did wanted to make sure I separated the country code from the number, but with people using (), -, and . as their formatting, it would never be the way that everyone would write it. All of the extra characters are not ITU standard. Just the +, and numbers. With that in mind, I write my numbers as +(country code) subscriber number. Therefore, my cellular number will be +1 4126829751. As you can see, I have no other characters, and I do not have spaces. However, I wanted to make it easier for people to recognize the country code so they can make the best decision if they should have to call me on an international scale.
Exceptions to this is my contact cards. Since I am not going to travel, everyone I would give a card to will likely live in the US. With that in mind, I place a space after the +1, third, and sixth numbers. VCF files combines the number entirely making it completely ITU standard.