So I took over a network recently where they using a very large subnet (10.4.0.0/16). Of course a subnet can never be that large, but I didn't change it as they had a lot of servers and other devices in production and didn't want to change subnets. They are now using about 350 IP Addresses from this subnet. Infrastructure is Completely Cisco. All switches are Cisco 3560G's. What is a safe number to grow this subnet before I should start another VLAN?