I had 150 letters to mail. I ran out of the Easy Close Envelopes at 100. Normally I’d wait until the next day and buy more at Staples. But they needed to be post marked that night. My reserve envelopes required my saliva tasting horrible glue and holding the envelope flap until the saliva dried! So sooo time consuming. Don’t put yourself or anybody else helping you through this burden when for pennies more using Easy Close Envelopes speed your project’s progress.