Are you still tapping the spacebar twice at the ends of your sentences? This practice was very important for readability of typed documents for a long time because typewriters used fixed width fonts (meaning each character, including spaces, were the same width). Therefore, adding that extra space made it visually clear for a reader where sentences ended and began.
Today, the fonts we use in our word processors are variable width fonts. They are designed to handle the beginnings and ends of sentences without that extra spacebar tap. In fact, adding that extra space these days is actually distracting for a reader, especially when reading text on screen.
