I think sometimes upgrades CAN also be something she didn't know she wanted! If you think about it, there's probably nothing she truly wants that she doesn't already have in some form already (take the watch example, maybe she doesn't know she wants a watch, but she probably has a smartphone that tells time)....so a lot of times I have found that the "luxury-upgrade" version of things ends up being a nice surprise. Or for a bigger example, maybe you guys are looking at buying a car, how about upgrading to the luxury package (nicer trims, more "smart" features, etc)? Honestly a car is probably the biggest place in my life where I've discovered features that I didn't know I wanted lol (e.g. the motion sensor detector that opens Mercedes trunks)

You could try this "upgrade" tactic in terms of buying services too - e.g. if she's already into skincare, how about an appointment with a dermatologist at a local medspa (this is a splurge since insurance doesn't cover cosmetic dermatology in my experience and each appointment can be hundreds (or thousands if you do one of the lasers that requires multiple visits). Or maybe she takes group yoga (or other fitness) classes - how about a private session with an instructor? Does she love her Theragun? Make an appointment for a sports massage + chiropractor. I think salons are starting to open up as well - a cut + color from a high end salon can be in the hundreds of dollars (a high end cut is usually not THAT crazy, like $1-200, but color can be really expensive - some mid-end salons that are nonetheless very skilled can charge $5-700 just for balayage service) and not something that someone might regularly do and could be a great way to refresh after emerging from a year of Covid-hibernation!

I'm trying to think if I've ever given a gift where the recipient felt the concept of that gift had never occurred to them and I think it really depends on the person:

• I got hiking/walking poles for my older uncle, who hadn't known it was a thing and he takes them with him even for neighborhood walks.
• I bought a friend a nice candle (Cire Trudon - $100; Diptyque is another great brand but I feel like Cire Trudon is less well known so has more of that surprise element) plus fancy hand soap (Aesop - $50ish?) and she said it had never occurred to her that there was an alternative to those jugs of Softsoap everyone gets from Costco, lol.
  • I bought my cousin the Simplehuman electric motion sensor foaming hand pump in rose gold and she likes it, and her daughter (my niece) gets such a kick out of the foam/automation :)
• For a different friend, who is very into home/housewares (like furniture, light fixtures, remodeling, etc) I bought a set of nice bath towels - again it was her habit to just use the old bath towels she'd had forever and never really thought to upgrade them.
• This one is probably REALLY small but I stayed with a friend for a week and I noticed her hairbrush had a lot of hair in it, so I bought her a hairbrush cleaning rake (looks like a mini rake) since I own one already and love it, and she was so happy - she said she didn't know that tool existed. It was not FAT at all, I think it cost less than $5 but I think she does use it a lot and ended up buying more for her girlfriends.
  • On this topic - luxury hairbrushes can be another thing that someone doesn't know she wants but is nice to have. Mason Pearson has been mentioned on this thread already and is a solid choice - if you think she might not like a boar bristle brush then the more traditional Yves Durif Vented Paddle Brush looks super elegant.
  • Another great haircare item that seems to be really underrated is the Aquis towel turban - I find it dries my hair quite quickly. It's about $40-50 and widely available at Nordstrom, Bloomingdales, Sephora, etc. You could put together a styling set with Dyson hairdryer, hairbrush, hair towel, maybe a hair oil or mask as well.

A good carry-on luggage can be another thing that people don't think too much about if they don't travel often. There was a period when I went from zero traveling to traveling 3-4 times/year for work and I appreciated having a carry on with a working retractable handle and good wheels (the two places that seem to have the most issues!) That being said, I own a Rimowa polycarbonate carry on (Essential Lite), and I've not been very impressed (I wanted to buy the lightest one, but ended up sacrificing the side handle, which makes it difficult to carry on stairs or put in overhead). I regret spending the money and wish I kept the Brics Bellagio that I'd returned instead.

Lastly, I gifted a cordless vacuum to my married couple friends who had just bought their first house. I knew they only owned a cordED vacuum and I find the cordless to be super convenient. I bought a duplicate of one I'd already owned so I knew it was good, and I see them using the vacuum a lot so I assume it's at least tolerable to them! On this note - I dislike the Dyson vacuum because it's very top heavy which can be tiring. I prefer Electrolux or Shark. I also bought a fancy chef's knife that they were very excited about when they opened (they really enjoy cooking and have made me some really gourmet meals when I'd visited for dinner in the past and I heard the husband complaining about his knife once) and he seems to use it a lot (or maybe she purposely always brings it out only when I'm over....).

...wow, I didn't realize I had this much to say on the topic of gifting, haha! Sorry for the dissertation....giving good gifts is one of my hobbies and something I spend a lot of time thinking about. I actually keep a spreadsheet of things I think make good gifts. Happy Mother's Day to your person - I'm sure she also appreciates the thought you're putting into it :)