With my twins, we used one until they were five and we needed it for our new baby. That baby is four now. The video monitor broke a year or two ago. We replaced it with just an audio monitor and it’s still in her room now. It really depends on your family and your home. We like it because we’d rather our little one call out to us than wander around the house at night if she needs something.
We use the miku pro. Quality is amazing!