Congratulations on winning this challenge
@cyclonenic!
Great strategies, everyone
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I did a lot of the same things as most people did. I bought cheap stuff at the beginning that I knew would have different named upgrades, quite a few mid-range priced items to upgrade. I had my Sim, Maria Fix-t (get the Sesame Street reference --- Maria ran the Fix-It shop?) skill up on the woodworking table, and sell what she made. After she could craft bathtubs, then, she could save up for a few more expensive upgrades (the cheaper hot tub, the microscope and the telescope) Her aspiration was nerd brain (she didn't finish it, but it helped her to want to level up in handiness --- traits: genius, dance machine (disco naps are great and the cheapest radio was one of her upgrades,) and loves the outdoors.
She had an unpainted/unfinished floor 5 by 5 bathroom with one cheap overhead light and cheap door. Then, there was a 2 by 2 unpainted/unfinished floor/cheap door room with a cheap sconce for storage of completed items that I didn't want to distract her. All of her other stuff was outside. When she completed upgrades on things that were too large to fit in the storage room, I shoved behind the kitchen counters so she couldn't use the cheapest microwave that says it was made from parts of 80s children's toys, get into the bathtub, for example (she had a shower that was usable).