Siemens mature devices

So we use OP277 and OP77B both of which are in the discontinuation phase. Although both will end production in Oct 2014, Siemens makes a big point of service and spare parts being available until Oct 2022. Sounds good. Makes one think there's plenty of time (years), to make the migration. BUT, I've sent at least 4 OP277's for repair. NOT ONCE, have I actually received a repaired unit back. It's always been a case of it's not worth repairing, or some other reason - we'll replace the unit for only X dollars, which is about half the price of simply buying a unit without exchanging one. So, do I really have until 2022, or am I actually going to have a problem when I run out of spares in a couple of years? Will I find myself receiving a KP700 comfort panel instead of an OP277? When should I start hitting this, as it requires re-programming of the K keys, and different software (WinCC v WinCC flexible).

They guarantee that you can replace the panels until 2022. So yes you can get a similar panel in return if you insist hard. But they will hike the prices up progressively so that you will be urged to consider migrating to a different panel instead.

Already a new KP700 costs the same as a new OP277 used to cost, only the KP700 is a much much better panel.
My main gripe with the comfort panels is that you also have to switch to TIA for the PLC program if you need integration. If it wasnt for that it would be a no-brainer to switch. I have heard rumors that v13 should allow integration with classic STEP7 v5.5.

We've got 3 or 4 spares. Plant is 6 years old. We use 6 OP277's. 4 have been replaced over the life of the machine. I'd expect to have to replace 1 or 2 in the coming year (biggest problem is sticking buttons). So I probably should sow the seeds in that management's mind? Would you f you were me? (Not an engineer, so others will be doing the work).

I would definitely sow these seeds. Tell them that it will be cutting costs in the long term. That should make them happy.