If you need it, use some kind of fence bracing to counter possible sideways stress caused by snow loads, falling tree limbs, and deer impacts. If you figure these things will not be a problem, especially if you live in the South or West or have a very short fence, you may decide to forego bracing. Otherwise, foregoing bracing will be risky.
We tend to prefer earth anchors over brace posts because earth anchors are affordable, inconspicuous, and effective. for a detailed account on the pros and cons of earth anchors and brace posts see Deer Fence Options: Fence Braces.
If you decide to use brace posts for your fence bracing, note that they are sold in pairs. Get one pair of corner braces for every two corners on your fence, one pair of end/gate braces for each gate, and one pair of end/gate braces for every two ends (places where the fence will terminate at a building, wall, or other fence).
If you opt for earth anchors, you can avoid having any cables hanging off the fence line by using two earth anchors per corner and attaching them to your corner approach posts rather than the corner post. Using this approach, plan on installing two earth anchors per corner, two per gate opening, and one per end. Then get 100 feet of 12.5-gauge high-tensile wire (offered right next to the earth anchors) for every 8 earth anchors.
Post Accessories and Tools
If you are getting round metal deer fence posts, prevent your fencing from sliding down the posts by getting a brace band for each round post and two for each gate. For our round posts and access gates get brace bands for 1-5/8-inch posts, and for driveway gates get brace bands for 2.5-inch posts.
If you are using round posts with drive sleeves, get one drive cap for every 20 posts. If you are using angle-iron posts or round metal posts without sleeves, get a manual post driver.
Also consider getting a digging bar. This is very handy for proving your post or sleeve has a clear path downward. If you only need to go 2 feet down we offer a 4-foot digging bar that is less expensive than the 5 and 6-foot digging bars generally available locally. However, if you need to go deeper than 2 feet, as you do with drive sleeves, you should get a 5 or 6-foot bar.