Give it a month of day in, day out all weather riding through the winter. Those mudguards, rack and yes, some form of luggage, will be more than worth the groupset upgrade. Especially as the salty grime corrodes the parts and the chain is ground down by road paste and washed clean of lubricant every other day. There is a lot of truth in what Winston says.
For the record, here’s my commuter expenditure break down:
Bike – used Kona Paddy Wagon (£220 of ebay) plus some nice new wheels, so about £500 all in.
Mudguards – SKS chromoplastic (£30)
New tyres – Schwalbe (£80 including tubes)
Rack – Topeak £30
Lights – Exposure Strada £250 front, rear b and M, cateye and mudguard £50
Pannier – Ortlieb Downtown £110
New saddle, stem and seatpost £200
And when you add in clothing, very roughly bike expenditure is the same as the accessories is the same as clothing. In fact clothing may be the outright winner based on the cost of nice winter boots, wind and rainproof tights and a nice coat/shell. Come January, it’s all about the clothes and accessories 😉
Still cheaper than a car and vastly more fun.