How much does bike price correspond with maintenance needs? In this question (with this answer) I asked about a commuter bike, which is to be ridden 40 km every weekday, in the city. And apparently for this scenario I can choose either of two possible kinds of bike:


A $700 bike with derailleurs, rim brakes, and 700 wheels ... I image that this is an extremely standard, common type of bike.
A $1250 bike with hub gears, hydraulic disc brakes, 700 wheels, and carbon forks and seat post ... these are higher-end features and it's rare to find them so cheap (and may require a much less local LBS).


I asked at a LBS (whose specialty is commuter bikes) about, what is the difference between say one of their $600 and $800 bikes; and the answer was, "better components, more durability": that more expensive wheels are 'stronger', etc.

I don't have any insight into how much, quantitatively, more-durable versus less-durable means.

Some arguments (perhaps the main/only arguments) for hub gears and hydraulic brakes are "less or no maintenance".

How much maintenance (not just what type of maintenance, but how much) does a cheaper bike require? How much less does a more expensive one? And/or, how much longer will more expensive components last? Might the more expensive components actually be more costly to maintain (because they're more difficult to service and more costly to replace), but require service less often?
The cheaper bike will probably require you to adjust the brakes and gears plus lube the chain every week or two, and a bike shop to replace the brake pads, chain and cassette every 3-20Mm. For you, that's probably twice in the winter, once in the summer. With rim brakes you will also need new rims/wheels every couple of years, more often if the roads are gritty. But a lot depends on your riding style and the enthusiasm you have for maintenance (hence the 3-20 range). If "lube the chain every week" actually means "the bike shop does that every month or two", they'll probably be putting on a new chain. Count a monthly service at ~$50 and the chain/cassette/pads as $200 and that's $1000/year in maintenance, or $600 if you do the monthly service yourself.

It's important to note that you can skimp on all of this and it just means slightly more expensive fixes and a slightly worse riding experience (gears that skip under power, more resistance from damaged bearings, cables or chains the break, brakes that don't really work). When I was a mechanic I saw bikes where basically everything needed to be replaced, but people were still riding them (and just wanted a puncture fixed or a new basket or something). The bad riding experience means an hour for your 18km commute instead of 40 minutes.

With hub gears and disk brakes, especially with a full chain case, you'll lube the chain every couple of months, put new brake pads in every year or two, and I expect that replacing tyres will become your main dirty maintenance task. With a single-cable hub (Shimano, SRAM) you'll have to adjust the gears after a couple of months (the free service) then again a few months before you need a new gear cable. If you run Marathons or some other puncture-resistant tyre you should wear the tyre out without getting a puncture (a puncture is often the thing that makes you look at the tyre and go "need a new one". I run a Marathon Plus on the rear and have only had one puncture in at least 20Mm. I did get a 3" nail through one though (with no puncture!)

Those numbers are why people often end up with a dedicated commuter bike that costs a fortune up front. New Rohloff Oil every year at $20 compared to a new Shimano hub every three years at $800 makes the $2000 up front cost of a Rohloff seem cheap (a Rohloff will last 100,000 kilometres or more... no-one really knows because there aren't many hubs that have done that distance yet, Rohloff only started about 10 years ago).