Play time – how much

My pup is a 4.5 month old maltese. She's eating well ans has learnt basic training commands.we spend about a hour a day playing with her but the rest of the rime she either plays by herslef or just follows us round the house like a shadow. We do have an older dog who she is also attached.to but does not play. How long per day do you play eith your pup? Is it ok for them to play alone and learn how to manage boredom Thanks in advance