I kinda gave myself this headache on accident but whatever when writing numbers should I spell the number out or just make it easier on the poor reader and put the numbers in Ex. - 500 or five hundred
There are numerous stylebooks, and here is one-- The Chicago Manual of Style (15th edition), Rule 9.1: "In nontechnical contexts, the following are spelled out: whole numbers from one through one hundred, round numbers, and any number beginning a sentence. For other numbers, numerals are used. For the numerous exceptions and special cases, see throughout this chapter and consult the index." And there are lots of exceptions and special cases, but at the early stages of writing, at least, I find this to be a good rule to follow.
I'll add this: spell out numbers in dialogue. Don't know if Chicago or AP cover this, but when I read fiction, that's how numbers are treated.
But I wouldn't worry a whole lot about it -- if you get to the publication phase the publisher's editors will apply their stylebook anyway.