Well since you're using a bunch of the same mesh, it only has to load that one mesh once, then instance it throughout the level. If you uniquely modeled everything, even repeated details would have to be loaded multiple times. Instancing the geometry should make it more efficient.
Regarding the UE4 subscription, 2 things:
You can pay the subscription once, then cancel and continue to use the version you downloaded. The monthly subscription is just for updates. Personally I would recommend waiting until the next version (4.7) comes out before paying, then download it and cancel your subscription.
Secondly, if you are a student, you can get it completely free from the Github student developer pack here: https://education.github.com/pack
The Github subscription lasts for 1 year if I remember correctly.
Replies
Take a look at this thread which goes over some modular workflow and tips. It's for UE4, but the principles should work in UDK: http://www.polycount.com/forum/showthread.php?t=144838
You can pay the subscription once, then cancel and continue to use the version you downloaded. The monthly subscription is just for updates. Personally I would recommend waiting until the next version (4.7) comes out before paying, then download it and cancel your subscription.
Secondly, if you are a student, you can get it completely free from the Github student developer pack here: https://education.github.com/pack
The Github subscription lasts for 1 year if I remember correctly.