Depends on what you are trying to contain. There is a business an hour away from me that sells the pre-made continuous fence panels. They have 5-bar panels that weigh 275 lbs. per panel that are really heavy and I would use those for bull pens, rodeo arenas with rough stock or anything where you are breaking broncs to ride or otherwise dealing with wild critters. I have always used their lighter gauge panels that are less than 200 lbs. each and have 5 bars with 1½ inch pipes that are probably 12 or 14 gauge. They also have some 6-bar panels that are lighter yet. Some people plant wood posts and bolt the panels on with clips. I have always used pipe for posts and welded about 3 of the bars to the post and it has worked great. They are easy to cut off the pipe post with a cutting blade on a 4½ inch grinder if you decide to change the configuration down the road.