Remote Support Keeps Machines Running: How EtherNet/IP & remote access servers allow machine builders to securely and cost-effectively help manufacturers cut downtime. From the March edition of “The Journal from Rockwell Automation and Our Partners” magazine.

I'm working on doing this now. Most of my experience is with Allen Bradley, but I've worked with a lot of others. Have a good day, Randy

My experience is that customers deny us remote access on the basis of the risk to their internal security. They don't seem to grasp that it is possible to allow us restricted access only to the equipment we seek to support without compromising the security of the millwide network.

Remote Support helps a lot by saving the time and cutting down the service costs by avoiding the travel & other expenses. But has its own limitations based on the nature of the trouble and quality of connection infrastructure.
Secondly, the point mentioned by Ken Natton is true with some clients.

@Ken Natton: You are bang on there. To add to your point, customers can also restrict when a remote connection can be made and even for how long it can be established for.

Until recently I had always been in an engineering role, and it was very rare for customers to permit us to have remote access. This did present serious practical difficulties in the period after start-ups. By chance rather than preference, I currently find myself in a service role and there are some of the customers we support who do allow remote connection. It is no exaggeration to say that sometimes, when a problem can be dealt with remotely, it is dealt with within ten or fifteen minutes. On the other side, it is not unknown for me to be called out of bed in the small hours by a customer who does not allow remote connection, only to be told on arrival on site that they have already solved the problem. It still costs the customer a significant amount, but they seem to just accept that. It all seems so unnecessary to me.

It is ironic that a remote connection to a system, almost certainly implemented via VPN, is likely to be much less of a security threat than that posed by a PC on the remote site that is used to surf the net during a lunch break etc.