This all comes down to your personal situations and preferences. I would always recommend the fitting a moderator, if only for the benefit to your hearing. Prolonged shooting without a moderator fitted will cause irreparable damage to your inner ears. Moderators can also reduce the felt recoil and muzzle lift of a rifle, making it easier to stay on target, observe bullet strike and make any follow up shots quicker. Also many stalking leases, syndicates etc. will require a moderator to be fitted to your rifle before you will be allowed to shoot. However, the use of a moderator is not completely necessary. During my time as a gamekeeper in Germany (where moderators are prohibited in many places) I shot many rifles without them, albeit with ear protection. While notably louder and livelier, the handling, weight and balance of the rifles was certainly a bit better and with no moderator fitted, iron sights can be used, which can be popular for driven hunting. If you do not opt to use a moderator, I would advise that a good set of quality ear defenders are essential.