After a couple of far from satisfactory repairs by halfords I now do all my own maintenance.
I also recently built a bike from scratch as to get a complete understanding of how everything works.
That way there is nothing I cannot repair and I tend to nip any potential problems in the bud rather than let them escalate to the point where I would have to take it in for repair.
after initially worry about every task ahead i found everything quite straight forward once you actually get the tools out and make a start, using only supplied component instructions and park tools online information was excellent for the times I could not make sense of said supplied instructions.
And on the couple of a occasions where I needed help or reassurance with anything this forum came up trumps.
the best advice regarding any maintenance is have patience and the right tool for the right job.
And if you are unsure of what you are doing a little reading will put you right as once you understand how something works and not that it just does if you do this makes emergency repairs when you are out and about easier,which could save you a long walk home.