Thanks to my preparedness, none of the paint leaked through and I had ZERO (yes, ZERO) touch ups needed. How? Here is what I learned and what worked for me:
1. Look at SEVERAL photos of striped walls. This will help you decide horizontal vs. vertical, fat vs. skinny and bold vs. neutral. I knew I wanted to use the two colors connecting our hallway to our family room - a light and dark neutral. I also knew I didn't want extremely fat stripes and feared doing skinny stripes in case I would have a ton of touch ups.
2. Hold a tape measure up against your wall. Play around with different widths. Make pencil marks and keep them on the wall for a few days so you are certain they are the width you want.
3. Use frog tape - it's the green painters tape, rather than blue. I read a few blogs that swore by this tape and said the blue tape caused leakage.
4. Have someone help you tape the stripes and use a level! It may seem daunting to use a level, but trust me - you don't want to be staring at crooked stripes every day.
5. Use a credit card to seal the tape to the wall. This helped A LOT! I found that in several places, the tape wasn't entirely secured to the wall.
6. Before painting your darker stripes, first paint your base color over the tape. This will prevent any leaking because it seals the tape.
I love the way our hallway turned out. It almost plays tricks on your eyes making you think the hallways is deeper, which I love. Another project checked off of our list - and I am happy to report it was a SUCCESS! Now onto the downstairs half bath :-)