Retirement planning is both pretty straightforward and complex at the same time. My wife and I have backgrounds in finance, so I guess it is something we thought about for years before we both retired a few years ago (she several years before me). The simple part is that your cash inflow (income and whatever principal you can afford to spend) has to equal your outflow (expenses) - and you can come at it from either side.
So you might determine what you think you would need to spend each year for everything, including diving trips - and then compute how much savings/investment you would need to generate that cash. You, of course, probably want to minimize the cash needed, and there are lots of ways to do this (the complex part). If diving is really a big deal for you, then you really might want to look into moving to somewhere where the living is easy, cheap, and dive-friendly. My sister retired to "old" Florida, where the cost of living is pretty low (at least relative to New England, where I'm from). She and her husband do lots of shore diving in the Florida springs (just the cost of air) and the occasional boat dive off the east coast, where they occasionally get a reduced rate deal for locals with the dive op where they got certified.
The other approach is to estimate how much financial resources you think you will have on retirement, plus any payouts from a retirement plan or social security (or whatever the equivalent is). That's what you have to work with, and you need to make your budget fit that. Also remember that you can eat into your savings a little if you have to. The ideal is to have enough funds that you can live off the interest/dividends plus what you get from social security, and never have to use any principal. But then you will never get the pleasure of spending that principal. The rule of thumb is you can spend 3-4% of your total savings plus income each year. Better than rule of thumb is to create a spreadsheet that has for each month (each row) a column for current savings balance, expected misc income, total available (the sum of the first two), expected interest earned on that money,if invested (expected interest rate times the total available ), other income, then add all the income (interest, soc security, other misc) to the beginning balance and subtract expected expenses to get an ending balance. This becomes the beginning balance for the next month (row). create enough rows to cover you from now to when you reach, say, 100 years old. Now you can play around and see how long your funds will last based on various estimates of income, expense, and interest rates. Oh, and if you want to get fancy, estimate a monthly inflation rate and multiply each monthly expense by that to get the expected inflated rate of spending over time. (I said it could get complex).
Depending on the gap between what you think you will need and what you think you will have, and how many years before you retire, you can come up with a maximal savings/earnings plan for the next few years.
I know some people say spend and enjoy now while you can, but I'm of the balanced school which says enjoy life now but life does not stop when you retire, so you will want some financial ability to keep active and alive, at least for a while.
As I posted in another thread on purchasing island property, we were able to find a property on a nice Caribbean Island that we use for several (winter) month per year plus a few additional 2-week trips, and this is where I do all of my diving. We rent the place when we are not there, and so far the rent has covered 100% of our costs each year, and the appreciation has matched what we would have realized by investing the money in the financial markets instead. So essentially a free property. And I get a local resident rate at a few of the dive ops here (only $30 to $60 per 2-tank boat dive), which is something I have seen at other locales as well. And by being here long term I have met several folks to go shore diving with. So those are benefits as far as keeping diving costs down.
Good luck
@Dogbowl !!
