Wow, that's a lot of laundry! Considering fresh water, energy usage, refuse/landfill use, waste water volume... I wouldn't call myself a 'big green mama' but that's a big footprint your leaving on the environment every month. Your probably spending $120 a year just on pillows... Not sure how frequently you buy laundry detergent (at $20 a container these days; lets say you use one jug every month... that's $240 a year just laundry soap) and fabric sheets, etc... plus the cost of water, heating, electricity... I would imagine your sheets and bedding (especially anything with elastic) wear out more often due to all that washing too. It wouldn't surprise me if your spending at least $500-$700 a year just on the cost of replacement bedding and the cost of doing laundry just for your bedding.
We change bedding once a week.
I don't think I buy "expensive" pillows and pillow covers and pillow cases, but they are more than $4-6. Typically I get regular pillows for $20-30 (Target) and for my husband, he has the $100 memory foam sleep/neck pillows from the back/sleep store. I replace my daughters 2-4 times a year, or as necessary (especially while she was potty-training and would have nighttime accidents); my husband's is replaced every 2 years (he won't let me replace it sooner because he says you have to break it in for it to be comfortable). He also has a body pillow; that is replaced 12-18 months. My pillow is replaced every 12-18 months. But I also use multiple pillow covers (1) and pillow cases (2) on each pillow.
However, if you are buying $5 pillows, you probably do need to pitch them often. I'd expect the cheaper poly-fill to breakdown down quicker and not provide good neck and spinal support--That may also explain why your husband's pillow looks like a "mangled mess". The cheaper poly-fill is probably not adequate in supporting the weight of his shoulders, neck and head longer than a few weeks.
Since you have allergies, you might want to familiarize yourself with the pillows and pillow case protectors that are made to guard against allergens. Also, keep in mind that often cheaper products may contain inferior components, chemicals and materials that could increase symptoms of an allergy reaction.
As for liking the fresh smell of laundry... YOu might also want to keep in mind that the perfumes and fragrances in commercial laundry soap contain a lot of chlorine, phosphates, and petroleum-based chemicals. You're putting a lot of that into your your home environment/breathing air and onto your skin. Seriously, if you are prone to allergens, you might want to consider how much of your sensitivities may be brought on by constant exposure to these chemicals.