I love our sectional sofa. It is comfortable, and it's scaled appropriately for our small living room. What I don't like, is that you can't buy off the shelf slipcovers for it. When you own a Golden Retriever, shedding is a way of life. In order to keep the couch in like-new condition and keep things comfortable for dog-allergic guests, we keep it covered on a day-to-day basis. The covers come off when we have guests. The canvas layer on the bottom is laundered when we have people over -- we strip the couch and throw everything into the washing machine! The top layer (actual furniture covers manipulated for the configuration) gets cleaned every two weeks. We are using arm covers and pillows from an older sofa and bring out the pillows that came with it when we have guests.
If I really wanted to, I could take the cushion covers off and put them in the washing machine -- I've done that once before. I do periodically pull out the cushions and shift them around so that they will wear more evenly. I had considered treating them with an anti-mite spray, but I doubt any skin or debris gets below the upholstery since we keep everything covered.
The make-due couch situation is just the most sensible approach at this point. One of these days I might price a custom slip-cover but I'm really not sure it would make much difference. Where I do, however, think it makes sense to go custom, is with the window treatments in the room. We had curtains as a temporary solution but have always wanted blinds. They're easier to clean and also hypo-allergenic. This is a clean look we had in our old house and I knew I wanted to recreate it when we moved in. It's not just that I am boring, blinds like this are practical and they block out light that interferes with our television.