I have a Meyer lemon that I keep in a container.  It's not super large - the container is about 18 inches deep and 18 inches across.  Every year it provides a bowl of nice tasty lemons.  I've had this shrub - too small to call it a tree - for about 16 years.  The lemons are good for making apple sauce or other baking.

During most winters, I bring it into an unheated room indoors for the winter.  There it sits, almost never watering it.  Last winter I gave up, left it outside thinking it would die.  It was a mild winter, and it did not die.  However, it got mildew on all of the leaves.

I decided to keep it.  I removed it from the box I was growing it in, cut off most of the branches to make a nicer shape, cut off about half of the roots, and repotted it.  I fertilized with a citrus fertilizer.

It came back, has put out a lot of lush growth, bloomed a few flowers but none set. 

The only challenges are keeping it watered in summer, and having a dry protected place in the winter.  It's good to let it dry out for a month prior to bringing it indoors, such as placing it under the eaves.  I do the same treatment for geraniums.