Re: Putting in a fence - what length of post??
The rule of thumb is 1/3 the length of the post needs to be in the ground. An 8' post would be set 2.5 feet into the ground, leaving 5.5' above for framing, plenty for a 6' fence.
You may want to consider a steel post such as a Postmaster brand or a Z post. The framing attaches directly to the ears of this style of post, making them easy to cover the posts. Steel will outlast your life time on the property, whereas wood will likely need replacement within about 10 years, particularly being set in concrete. If you go with steel, I 'd recommend what I've mentioned here over chain link fence posts because chain link posts require brackets to attach the framing and they stand off from the fence, making them unsightly and difficult to conceal.
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