Opinions differ on this issue. However, it is the case that with modern rechargeable batteries, e. g. lithium-ion batteries, no precharge time is necessary as long as the battery is well cared for in its further life. The so-called memory effect is no longer present in these smartphone batteries and so you can start playing right away when the new smartphone arrives. So don’t panic if you haven’t left the battery of your new smartphone charged for 24 hours. This is not a big deal and is unnecessary, because with good maintenance of the battery you will still have a lot of fun with your smartphone.