I want to use powershell to alert me when an error occurs in the event viewer on my new Win2k12 Standard Server, I was thinking I could have the script execute every 10mins but don't want to put any strain on the server just for event log checking, here is the powershell script I want to use:

$SystemErrors = Get-EventLog System | Where-Object { $_.EntryType -eq "Error" }
If ($SystemErrors.Length -gt 0) {
  Send-MailMessage -To "[email protected]" -From $env:COMPUTERNAME + @company.co.nz" -Subject $env:COMPUTERNAME + " System Errors" -SmtpServer "smtp.company.co.nz" -Priority High
}

What is a safe frequency I can run this script at without hurting my server?

Hardware:

Intel Xeon E5410 @ 2.33GHz x2
32GB RAM
3x 7200RPM S-ATA 1TB (2x RAID1)

Edit:

With the help of Mathias R. Jessen's answer, I ended up attaching an event to the application & system log with the following script:

Param(
    [string]$LogName
)

$ComputerName = $env:COMPUTERNAME;

$To = "[email protected]"
$From = $ComputerName + "@company.co.nz";
$Subject = $ComputerName + " " + $LogName + " Error";
$SmtpServer = "smtp.company.co.nz";

$AppErrorEvent = Get-EventLog $LogName -Newest 1 | Where-Object { $_.EntryType -eq "Error" };

If ($AppErrorEvent.Length -eq 1) { 
    $AppErrorEventString = $AppErrorEvent | Format-List | Out-String;

    Send-MailMessage -To $To -From $From -Subject $Subject -Body $AppErrorEventString -SmtpServer $SmtpServer -Priority High;
};