Your wooden gate post hole should be a third to a half of the height of the post. Also, note that the diameter of the post hole should be three times the diameter of the post. You should set the post in concrete to ensure a long-lasting and durable post that will withstand the test of time.

The lifespan of a fence can range from 5 to 50 years, depending heavily on the material, local climate, and how well it is maintained. For example, a wooden fence might last 7 to 15 years, while a vinyl fence typically lasts 20 to 30 years. Metal, composite, and glass fences have some of the longest lifespans. Proper maintenance, such as regular cleaning, inspections, and staining or sealing for wood, is key to extending the life of any fence material. Vinyl and composite are durable options that don't require sealing.

Removing fence posts that are set in concrete is something you can't do by hand. You will need an excavator, a strong post-puller, or a jackhammer. If you plan on recycling the concrete base, you may be able to cut the post out with a jackhammer and then set the new post in the existing base. However, it's usually better to remove both the fence post and concrete together. Due to the weight of concrete, you will need a hydraulic removal tool.

Proper installation can make a big difference in your fence's maintenance needs. For example, wood fences that aren't installed correctly can be more likely to rot. While it's possible to DIY a fence installation, hiring a local fence company can mean much less work for you in the long run. 

A professional fence installer will make sure your fence is positioned correctly and installed in a way that ensures longevity and limited upkeep requirements.