Pipe fence posts run 8 to 10 feet apart. Wire fence t-posts run 8 to 12 feet with braced, concreted corner assemblies doing the real work. Privacy fence posts run 6 to 8 feet to carry wind load. Gate and corner posts go deeper and heavier than the line, always.
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Spacing rules follow what the fence resists. Welded pipe fence carries loads through its rails, so posts at 8 to 10 feet keep rail spans stiff enough that a leaning animal meets steel, not spring; closer spacing at gates and working pens where pressure concentrates is normal. Wire fence works by tension, so its line posts (t-posts at 8 to 12 feet) mostly hold wire height and spacing, while the corner and end assemblies (braced H-frames, set in concrete) anchor the tension of the whole run; that is why wire fence quality is judged at its corners, and why a fence with 12-foot spacing and proper braces outlasts one with 8-foot spacing and lazy corners. Privacy fence is a sail: a 6-foot cedar panel takes real wind load, so posts run 6 to 8 feet apart, set deep, and the north-wind side of an exposed lot argues for the tighter number and steel posts over wood. Depth rules are as important as spacing: the working rule is a third of the post's height in the ground (a 6-foot privacy fence on 2-plus feet of buried post), gate and corner posts deeper and bigger because they carry cantilever and tension loads the line never sees, and concrete around anything that carries a gate. One local wrinkle: on the Blackland side, expansive clay works shallow posts loose over wet-dry cycles, which is one more argument for depth and concrete at every structural post. And before any auger turns: 811 utility locates, every time.