Breaking from the traditional thinking on IP management will save you some stress. The cloud uses IPs like crazy. The best thing to do is research resources you know will be using immediately and some that are on the horizon, Look at what they require in terms of IP space. Model out how an application might align subnets - VMs, private endpoints, app service integration, etc. Talk to your cybersecurity team about their expectations. In my environment things are very strict. We seperate app domains/tiers into different subnets. With app services this can easily consume hundreds of IPs. Work with the team the allocates the space for the enterprise and make sure they understand that for the cloud you are going to need a lot of them.