I am a single woman who has owned my home for more than 20 years. I have a privacy fence around the back yard. It was there when I bought the house. I have replaced almost all of the fence posts since I've owned the house. I noticed I have one to replace right now. The get rotten and break off. I have to remove the panels on either side of the post and just slide them over and lean them on existing fencing. I remove the broken post and then have to use the end of a strong pipe to break up the cement from the previous post setting. I remove the broken up cement from the hole. I get a bag of Quikrete, mix it up in my cement wheelbarrow, put some in the hole, put in the new post and tamp down the quikrete in the hole, fill around the post with the rest of the quikrete, use my long level and make sure the pole is straight and in line with the rest of the fence posts. I smooth off the top of the cement. I use a 2 x 4 or two to anchor the post in place until it sets. After it sets, I reattach the fence panels.
It is not that hard to do this, it is just some work. When I first bought the house, I hired this done. Then I had a guy walk away in the middle of some fence work (I think he was an alcoholic and I had given him some money that he HAD to go drink it up and he didn't show up again) and I had to get the backyard buttoned up again.
I have neighbors who have had broken posts in their fence for years, causing their fence to bulge where the post is broken. I have to replace a couple every year or so and I like to fix them asap because of the security.
Yes, someone could break into the yard if they wanted to, but the 6 foot fence helps alot. It keeps stray animals and unwanted people out. They can't see what is there and are not tempted by what they can't see.
You can hire this work done also.