Great question.  We always say start with a clean wall and clean hands and you can resuse the stickers many times.  We have some we’ve stuck over 50 times.  Note that over time because of the dust and residue that gets on the stickers from the wall and your hands, they may not hold as large of an item (such as a poster) the more times you use them.   We also sell Replacement Magnastickers if you have any challenges.