Conservatory (15yr old) double glazing blowing

[Fordian]

Usual PVC model, still sound apart from some steamy panes. Has anyone else had this? I assume you just bite the bullet and get each panel replaced as necessary?

Yes, 2 panes have blown in ours.

Though when we had to have a (different) window replaced once, I was pleasantly surprised to find it wasn't a big or expensive job.