While they aren't cheap, I have to say I LOVE the Bindaboo gate we used when Kodi was younger. It is a spring tension gate that has a step-through people gate in the middle. This might not seem like a big deal, but it gets REALLY old stepping over gates all the time.
And it really isn't just a few months for many people. Even though they may be more and more trustworthy about pottying, you may still find that they need to be confined to prevent chewing or getting into potentially dangerous situations. While our gate wasn't closed all the time as Kodi got older, we left it up, and used it from time to time, until he was at least two. It was money well spent.
Here is the gate we have:
We needed to buy two extention pieces to have it fit our wide doorway.
If that doesn't go wide enough, you can simply use ex-pens and zig-zag them across the space that needs to be closed off. We also have 3 ex-pens, and used ALL of them at times... Kodi went through a phase of wanting to tear bindings off all the books on lower shelves, so one was used to protect our built-in book shelves. Another was used to surround our Christmas tree, and a third was used to block a very wide opening between our kitchen and family room, first until he was reliably potty trained, and then (for longer) when he kept trying to eat the fringe on my expensive oriental rug!!!
There are still times that the ex-pens are handy, both for visiting dogs and when we need to keep him out of areas where workmen are busy... He's WAY too nosey, and prone to steal things from tool boxes!