I find 24 a bit shallow especially for heavy coats and such. It seems like the doors barely close over closets with 24" depth when they are full. What about splitting the difference?

Both palimpsest and dekeoboe make excellent points.

Another thing to consider is the type of door. If you choose that infernal contraption, the bi-fold door, you'll appreciate having extra depth so bulky clothing won't push it half open.

Thank you for the comments! Are bi-folding doors truly that hellish? I can't stand sliding doors because they only open half the closet and was hoping to find quality bi-folds that would operate smoothly and trouble-free, is that a fantasy? Has anyone been happy with bi-folds that are used daily?

Also, the Ikea PAX system would just have single doors. Although there would have to be two compartments. Like the picture below. I'd probably get mirrored doors.

We have bi-fold closet doors in all bedrooms other than MB. 2 BMs are being used as office. The closet is only 26 inches deep, DH leaves his office closet doors open.

I hate the bi-fold doors in my office and wish I have deeper closet.

The bi-fold door is 15" wide when fold. It means anything placed in the room, within 16" to the closet door has to be moved first to allow clearance to open the door. I would rather increase closet depth and use sliding doors.

In my office closet I have Container Store elfa mesh closet 6-drawer units with table tops. I love the units. But they fit very close to closet door track, which I wish there is more room between closet track and units. The tight fit feel suffocating.

When the time comes to reconfig elfa system, we will get rid of all the bi-fold closet doors.

There's a time and place for sliders and bifolds, but for me, they are a last resort for when regular hinged doors just won't work.

The depth of a closet depends on the width of the door. 24" is fine if the door is full width. If not, the depth should be28"+.

Bi-folds can work if they are made well and located so they do not interfere with other doors. Well made bi-folds will require a source better than Home Depot, etc. I have helped my kids remove them and store them under their beds in countless dorm rooms and apartments so that's one major advantage of this door type. No tools required.

Adding mirrors to the doors will make them heavy. That generally means swinging solid core wood doors with 3 hinges instead of cheaper doors.

We have a closet with bifold doors in our back hall for coats and jackets. It is 28" deep from back wall to the inside edge of the bifold door when closed. I would not want it any narrower.

We live in a small house with small bedrooms with small closets. One bedroom has a 24" closet to which we added generic bifold doors (no room for a hinged swing-out, don't like sliders). The doors work fine. But the clothes touch the back of the door, meaning the closet isn't quite deep enough.

I'm building a new closet in the other bedroom that will be 26" deep on the inside. You want a couple inches between the clothes and the doors, IMO. Measure your current closets and see what will work for your clothes.

I see no need for 30". I'd cut it back to what you need to use the 24" system you're going to put in.