bottom seal vs threshold

[seiyafan]

Does adding a threshold further improve the seal on the bottom to any significant amount? I am wondering if I should just replace the current bottom seal or should I add a threshold too.

 

[Zeke]

Just look for daylight. No daylight, you're good. Thresholds with the seal embedded get worn. Seals on the door bottom are better and are used on a smooth threshold. The higher the threshold the easier it is to use an indoor rug to catch dirt. That is for an inswing door, of course.