Well our DIY fencing is still tight 5 years later......
We used the quad bike to tighten it
Put the posts in by hand, using one of those hollow, two-handled post-knockers and dug the strainers, then back-filled the holes with stone and rammed it down hard with the sledge hammer. I've had to adjust gates but that's the only movement, bar one very wet place where I've had to add a 3x4 to the strainer recently.