don, I kinda get what you are saying here:
Firecalc will always give you the same or better survival rate in this scenario (better, because as the happy years go by you have a shorter life span to fund).
but on the other hand, as Firecalc totes up more "good" years in its database, then don't its assumptions get incrementally more rosy for all concerned? Add more years of double-digit returns and the 'canonical' return of 7% could creep up to 8%, tempting us with a higher SWR, which in turn might make a bad patch seem that much worse.
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People's advice about the projects and "mad money" are sound. Unfortunately the projects have some overlapping electrical and plumbing issues that might be easier and more cost-effective if dealt with in one fell (and scary) swoop.
[For those interested, we bought a house with a big yard and an empty, non-functioning "swimming pool" that is about 36" deep, currently lined with painted blue concrete in a state of decay. The theory was that the runoff from the gutters would be caught in this holding pool, but no water currently arrives. Underneath is ROCK. Very hard travertine. The rest of the yard itself is trucked-in fill on top of this rock. I would love to turn the hole in the ground painted blue pool into a "natural swimming pool" which would need to have a minimum depth of 9 feet. A scenario for a high-end install of this type here is something like €50-75k. You can do something cheaper, but I have seen a cheaper version and it is not worth doing if not done right. This is average and not counting extra difficulty that might be posed by excavation in our particular case.
The kitchen needs re-doing. That could be a smaller chunk on its own, but re-doing the kitchen means (to me) ideally also re-doing the root-clogged drains and septic (if I wash more than three pots at a time, the water starts backing up; we're at the point where we call the high-pressure hose guy 2x a year) which means digging up the yard. If I'm digging up the yard, then while I'm at it, I should take a look into the separate gutter/water recovery system that isn't working and get the water to go either into the pool or into an underground tank (that we would have to install and wire a pump for) so that we can use it for watering the garden. And if I'm digging up all that, then I might as well get someone to get the pool, gutters and septic all coordinated at once. At least that's what I'd do if I were in the US, but here I worry about finding someone I trust to even undertake all this. Meanwhile the yard is filled with medium-size oak trees so I'm not sure if they will survive extensive yard digging. We also have some major yard electrical issues that would tie into this, and we'd like to bring some faucets to other points in the yard from where they currently are, run new electrical to the front gate/intercom/light, to the greenhouse, new circuits.. (circuits for pool, too, if we do that..) yada yada yada. Not to even START on where the overflow actually goes for the hole in the ground painted blue current pool and if it is legal or not.. not looking forward to opening up that can of worms. Plus the existing pool wall is exactly on the property line (corner, with 3 different non-residential properties abutting) so negotiating with the neighbors will be interesting. Who knows if something that excavates rock will even be able to operate with such close tolerances.. Well, it would make our lives interesting, add a s***-load to the prop. value if it came out right.. and, I know that in 10 years I'm not going to have the energy for it. IF it gets done, I'd like to start sooner rather than later so we have more time to enjoy it.]
Or we could just move.