I'm a year round, all weather commuter. I save my nice, carbon road bike for this time of year (and fun, fast commutes). In the winter, I commute on my gravel bike (also carbon). My gravel bike gets a beating compared to my road bike, due to it's harsh life all year round (winter and at this time of year getting bashed about in the countryside and bikepacking). As my mechanic said last year when it when in for it's service: "This is definitely a bike you haven't been blowing kisses at". It gets a full service every year because it needs it- costs between £150-£200 depending what needs to be done. This year, I needed new chainrings. Last year, was just cable replacement. I replace the bottom bracket at least once a year- it depends how wet it's been. My road bike, gets a full service every 2-3 years. I've owned it 10 years and replaced the bottom bracket once.