As long as you choose really. My youngest pup never had soaked food - he just didn't like it. So he has had just kibble with a bit of soft food sometimes added since 8 weeks. I think some keep feeding soaked kibble until teething is finished so 4 or 5 months? And some feed soaked throughout the dog's life.
If the brand you're feeding has a 'junior' variety, then have a look on the bag and see when they recommend changing to this. As for moving onto adult food - depends on the dog. Mine's just been moved over to adult at 11 months as he is a skinny thing and i decided he might benefit from the higher fat/ protein content for a bit longer. But many people swap them over at around 8 months as their puppies start to put on weight. I think it's recommended to swap to adult food once the dog has reached it's adult height (which is often around 8-9 months, but can vary).
Hope that helps.
