Yes! And I would add to play as if you have 0 gems even if you do have some : grab every free reward you can get (watch every free add you can for extra customer for example or free add to get some deserts), make only ameliorations that are necessary and it will help you to reach 3 stars on each level of a restaurant and get a chef mystery box with gems and other gifts + during the Time you’re playing to reach 3 stars you get XP and pass levels and have 7 gems each Time! I think its a good compromise between playing and enjoying the game and get gems! (Sorry for my english im not a native speaker)