I always remember when I was a teenager, I was talking politics with my dad. My parents ran their own very successful business, they were worth a LOT of money at that stage - but came from backgrounds of factory worker/cleaner, so fairly humble beginnings. My dad told me that no matter how well off they were, he would NEVER vote for the Tories. It didn't matter that it was the party that was "best" for them based on their finances etc - he said you always look after those that are struggling the most, and that the Tories would never be the party to do that. My dad used to be a union rep as well, which solidified his thinking.
That conversation always stuck with me, and I really felt his words and his belief in them. So I've always had the same thought process. Not that I've ever been in a position where voting Tory would benefit me - but I know that my voting habits wouldn't change even if I started earning a 6 or 7 figure salary tomorrow!
On top of that, I wouldn't vote for them with their lying, corrupt ways, in-fighting, destroying the NHS, destroying the housing market for people not lucky enough to have bought years ago, historically privatising trains/utilities, all actions for a fast buck for them and not considering long-term implications for the country, PPE scandal, Johnson, Cummings, Brexit, making really, really sick people have to fight for benefits they are owed, for stirring up hatred towards immigrants in this country, Uni tuition fees, expenses scandal, voting to put up their own (huge) salaries whilst voting not to increase those of nurses, etc, the loss of so many NHS dentists, the contempt they seem to have for ordinary/every day people, destroying our education system by underpaying, making class sizes too big, over-zealous ofsted, pushing good teachers to breaking point, etc, allowing the energy companies to continue pushing prices up despite declaring record profits, stopping allowing headteachers discretion to take a child out of school meaning some families never go on holiday (not even in the UK)...
I'm sure there are so many more things, but this is getting me angry now!