I have not had a gastric tack on any of my dogs, but I haven't had a case of bloat, either.(Frantically knocking on wood).And that is with almost 20 years of dobes and danes in my house. Dane people that I know whose dogs have bloated have said that they wished they had the tack done, as it would have been much cheaper than the ensuing emergecy surgery...or God Forbid-loss of their beloved animal. It is a crap-shoot either way, as far as I am concerned. The tack doesn't prevent bloat, it just prevents the torsion of the stomach, which may or may not ever occur.As far as when to get it done, speak to your local vet, I have heard of them doing a gastric tack in conjunction with a spay or nueter. JMHO.
Stella