$name = Read-Host "Username?"

Switch ($name.length)
{
    {$_ -le 3} {"Name is too short min required is 3 chars yours is $_"}
    {$_ -gt 50} {"Name is too long max allowed is 50 chars yours is $_"}
    {$_ -gt 3 -and $_ -le 50} {"Name is good with $_ chars long"}
}