Fundamentally, if you want to retire (irrespective of age), you have to sort your finances out so you won't have any outstanding debt to service by the time you intend to pack in work. That requires you to live below your means when you are younger, get a paid-for roof over your head ASAP, and pay as little tax as possible so that as much of the money you earn as possible is actually benefitting you, not being handed over to muppet politicians to waste.
When I was younger, I concentrated on getting my house paid off early using my overtime earnings, whilst also putting some money into my work pension. Once the house was cleared, the overtime earnings went into tax-efficient vehicles, like taking a PEP/ISA out every year, employee share schemes, inflation-proof NS & I Index Linked certs, and putting some AVC's in my pension on top of the regular amount. I have had a cardinal rule of never paying the 40% tax, no matter how much I've earned. I've always diverted as much as necessary into share schemes/AVC's in order to keep my taxable income on the basic rate, when I had an exceptionally high earning year. I do as much as possible using salary sacrifice too, so I don't pay the 12% NIC's as well as saving the tax.
My unavoidable household outgoings have essentially hit a plateau now I don't have any debt to service, and I can easily live within my net earnings after deductions and pension contributions are taken out. I don't intend to work beyond 60, and hopefully will go PT a couple of years before that. Aim to be a receiver, not a payer, of interest. Don't pay to borrow other people's money - make sure they are the ones paying to borrow yours!
