Do you not sharpen them in between? I've had to spend hours sorting out knives that have been left far too long without sharpening, but my routine is to spend about 15 minutes sharpening them every weekend. Then they're always sharp and never get into a terrible state and need remedial work.
My knives get noticeably suboptimal in a couple of weeks without sharpening, so if I left it 6 months they'd be blunt pretty much all the time.
Usual advice is that you need to straighten your blade every week or two and then you can sharpen it every 6 months or even a year (depends on usage of course). To straighten the blade you use honing rod which many people mistake for sharpener.
I have a steel honing rod but it's never seemed to have much effect. Perhaps my technique isn't right.
I also have a ceramic sharpening rod, which I use to sharpen my breadknife. That's very effective, but different as it actually removes steel. I give my straight-edged knives a few strokes on each side on a 3000 grit whetstone every weekend, which seems to keep them nicely sharp. That will slowly wear them down but it hasn't done so noticeably yet so I expect the knives to last many years.
My knives get noticeably suboptimal in a couple of weeks without sharpening, so if I left it 6 months they'd be blunt pretty much all the time.