Were you taught to put two spaces after a period at the end of a sentence? I was and I think many people were, but now most publications recommend using just one. I recently had to go through my 75,000 word manuscript and remove hundreds of spaces at the suggestion of an editor.

The modern and easy-to-follow style is to put one space after a period.

The story of spaces after periods is often told as though monospaced typewriter fonts needed  two spaces after a sentence for good readability, and that the wide availability of proportional fonts on computers led to the switch to one space. In mono spaced fonts, the letters are all the same width, so an i is the same width as an m, but in proportional fonts the letters are different widths, so an i is much narrower than an m.