Vaccinating horses is part of horse ownership.  You can vaccinate your horses yourself.   Protecting your horse against tetanus and strangles is essential and every horse should be protected.  
Tetanus is a nasty disease that is almost always fatal   Tetanus organisms and their spores are found in the environment in the soil and animal faeces where they can survive for years.  Tetani may enter the horse through wound puncture or laceration  The most common source of infection is a wound that is often very small and may go unnoticed. Horses always seem to have some sort of abrasion even when they are in the safest of paddocks.   Tetanus will cause muscle spasms and lockjaw.  
Strangles is nasty! You want to protect your horse from this.  It is highly contagious between horses.  Your horse will be very sick with this.  He will have a high temperature  swollen lymph nodes which abscess and rupture. This discharge will come out the nose and it will contain very high numbers of the bacteria that causes Strangles.  The infection spreads by direct horse-to-horse contact or by humans, tack, drinking troughs, fences and from the environment contaminated with the infectious discharge.

Vaccinating your horse is easy.  Horses are generally very good with intra muscular injections.