The main concern is loading the slab before it is strong enough, potentially causing it to crack. Many contractors will tell you to stay off for seven days just to be safe, but most concrete mixtures used today will gain adequate strength within three days. A concrete slab may be open to traffic as soon testing confirms that it has reached a strength of 2500 psi.
Most properly cured concrete does not require a sealer but if you choose to use one it may help improve the longevity of the concrete, especially if you plan on using salt to deice your pavement. Most sealers are applied at around 28 days or later.
Although it may be tempting to roll up your sleeves, mix up some concrete, and tackle a concrete project yourself to save money, you will likely spend most of your time preparing for the project. From planning a complete and realistic budget to considering help from professional concrete contractors for certain steps of the project to making sure your project is allowed by the local permitting office, there’s a lot to do before you start mixing up that gray matter! Pouring and finishing concrete is hard work, and often the convenience of hiring a contractor outweighs the enticement of a challenge for most homeowners.