Scenery is something I always find something of a frustrating compromise. On the one hand I want to be able represent all kinds of terrain on my tabletop but on the other storage is always an issue. When it comes to open terrain such as grassland, scatter terrain will usually work well, allowing you to add trees, rocks or even bomb craters. The area where I find myself with the biggest dilemma is with linear scenery items; by which I mean things like river or roads etc..
One solution that I find works well is creating insert pieces. That way you can reposition your ford or rapids anywhere in your river you like depending upon your gaming needs. In the example below you can see a ruined road section, this saves me having to make and store extra road sections just to show damage.