Apparently I missed the other recent thread.

For me, I may or may not spend time cleaning the bike depending upon how dirty/greasy it is and what it is. Some bikes I will get down to toothbrush clean, others just get wiped down with a rag.

Basically the bottom line is to get the bike functional and make it safe to ride. Beyond that it all depends upon how much I have into the bike, what the local market is currently like, how desirable or easy to sell the bike is in the local market, and if I won't mind keeping it awhile if it doesn't sell.

Some bikes get posted for sale and then end up getting salvaged for parts if the complete bike doesn't sell.

Some bikes end up as parts bikes and the parts get several other bikes back on the road (often parts go to repair grandkid bikes).

Some bikes do get the full dismantle and clean and re-lube, and new cables and chain, sometimes new derailleur pulleys, new bearings, new tires and tubes, new bar tape. It really depends upon the bike and market value.

This is a hobby for me, not a business, some years I don't sell any bikes, some years I do, and usually I'm either just slowly upgrading my own stable of bikes or working my way towards something I don't currently have or do currently want. The past several years I've been scaling back and reducing the number of bikes I have and reducing redundancy.
And sometimes something comes along and I end up with redundancy again (like happened recently, oops).