As stated at the start of this month: I've been feeling it.
I've reached six months since I joyously switched off winter tyres and winter gearing, but, excepting the current temporary reprieve, the decline in weather has started. So since it was time for a tyre change (two months is the most I can get) and a chain change (two months there also) I thought I might as well switch to my winter gearing (19 tooth cog). I'm glad I did as the 17 tooth cog was already visibly worn, after just six months! Even though I'd been really good and changed my chain every two months; in previous years my bike has had to suffer severe neglect of maintenance schedules.
Last year I'd switched gearing at the same time I switched to winter tyres so didn't really get to feel the benefit: the additional weight and rolling resistance of the winter tyres pretty much cancels out any gain from the lower gear; which is why I use a lower gear with winter tyres, after all. But with the lightweight CX tyres the 42:19 ratio is really noticeable and a nice change! It's perfect for me off-road as I can now stay sat down instead of standing up for mile after mile; 42:17 was my gearing of choice on the road with slicks so it stands to reason it'd not be ideal off-road. I'm thinking I should probably make 42:19 my default ratio, give up the pretence of silly commuter racing and just get up 10 mins earlier in the morning so I still get to work with time to spare.