Retrieve the last backup date/time of SQL Server databases in PowerShell.

<#
    .SYNOPSIS
        Get-ISqlLastBackups
    .DESCRIPTION
        Retrieve last backup date/time of databases
    .PARAMETER serverInstance
        SQL Server instance
    .EXAMPLE
        .\Get-ISqlLastBackups -serverInstance Server01\SQL2012
    .INPUTS
    .OUTPUTS
    .NOTES
    .LINK

#>

param(
    [string]$serverInstance = "$(Read-Host 'Server Instance' [e.g. Server01\SQL2012])"
)

begin {
    [void][reflection.assembly]::LoadWithPartialName( "Microsoft.SqlServer.Smo" )
}
process {
    try {
        Write-Verbose "Get last backups using SMO for a given server instance..."

        $smoServer = new-object Microsoft.SqlServer.Management.Smo.Server $serverInstance

        $dbs = @()

        foreach ($database in $smoServer.databases) {
            $DBName = $database.Name

            if ($database.LastBackupDate -eq "01/01/0001 00:00:00") {
                $LastFull = "N/A"
            } else {
                $LastFull = $database.LastBackupDate.ToString("yyyy/MM/dd HH:mm:ss")
            }

            if ($database.LastDifferentialBackupDate -eq "01/01/0001 00:00:00") {
                $LastDifferential = "N/A"
            } else {
                $LastDifferential = $database.LastDifferentialBackupDate.ToString("yyyy/MM/dd HH:mm:ss")
            }

            if ($database.LastBackupDate -eq "01/01/0001 00:00:00") {
                $MostRecentBackupType = "N/A"
            } elseif ($database.LastBackupDate -gt $database.LastDifferentialBackupDate) {
                $MostRecentBackupType = "FULL"
            } else {
                $MostRecentBackupType = "DIFF"
            }

            if ($database.LastBackupDate -eq "01/01/0001 00:00:00") {
                $DaysSinceLastBackup = "Never Backed Up"
            } elseif ($database.LastDifferentialBackupDate -gt $database.LastBackupDate) {
                $DaysSinceLastBackup = ((Get-Date) - $database.LastDifferentialBackupDate).Days
            } else {
                $DaysSinceLastBackup = ((Get-Date) - $database.LastBackupDate).Days
            }

            if ($database.Name -ne "tempdb") {
                $database.Refresh()
                $db = New-Object -TypeName PSObject -Property @{
                    DBName = $DBName
                    LastFull = $LastFull
                    LastDifferential = $LastDifferential
                    MostRecentBackupType = $MostRecentBackupType
                    DaysSinceLastBackup = $DaysSinceLastBackup
                }
                $dbs += $db
            }
        }
        Write-Output $dbs
    }
    catch [Exception] {
        Write-Error $Error[0]
        $err = $_.Exception
        while ( $err.InnerException ) {
            $err = $err.InnerException
            Write-Output $err.Message
        }
    }
}