Mattress Forum

Here's my Q: all of the beds are these very nice hand-crafted wooden things...but they don't have any "slats" that run horizontally from the left edge to the right...I don't know much about beds, but my understanding is that it's always best to have good support underneath a boxspring/mattress so that it doesn't sag in the middle...kind of like this:

My noob question is whether supportive 'slats' like the above (or heck, even just a single horizontal metal frame like below) is necessary to prevent sag/droop over time, or is that basically what the boxspring is there for?  If it's a high-quality wooden box-spring, will that provide all of the below support needed to prevent mattress deterioration or is it wise to still have some sort of slats or frame below?