Shep has said the key thing here.....firstly personal decision and then flock history. This is quite right and i for one would never say do or dont over this! For example a friend lost some lambs from pasturella and I urged him to Hep P immediately and for the forseeable future.....it was a problem with the previous owners on the farm they had just bought, but they were not told this.
Cost will not come into it....or shouldnt

Toxoplasmosis is an interesting one - once a sheep has either had it or been vaccinated they are immune for life. A good friend of mine with much more experience than me told me 20 years ago what they and old shepherds would do to avoid it....and my vet who kept sheep agreed.....not scientific but seemed to work....
What they did was to lamb their 200 ewes outside in a field of about 10 acres with a large barn attached where the lambing pens were set up, the sheep lambed outside and were bought in to pens for 24 hours then let out into some fields amounting to another clean 10 acres the otherside. When lambing had finished all the shearlings were put into the field where the lambing took place for several weeks to get exposure to toxoplasmosis nasties that were lurking, catch them, get over it and become immune......then when they were put in lamb themselves in the autumn they had immunity and therfore didn't have a problem.
Now this worked for them for donkeys years.....they are retired now!