I think these discussions are valuable but could do without the snippy people. The costs are not set in stone, but for those of us without a starting point, every little bit helps.
Unfortunately I can't answer the question because we are still working and only vacation/weekend campers. However I try to glean a little bit when I can to apply toward our future full-time adventure.
We have been debt free for a long time and live simply but never really paid much attention to our spending. Since we are now about 2.5 years from retirement, I am starting to organize our finances and calculate our expenses.
There are a couple apps available for tracking income and expenses. I started using "Personal Capital" at the beginning of the year but hear that "Mint" is also a good one. I see some mention Excel but I am clueless on setting up and using that tool.