leaving in 10 days, no kids, 20th anniversary!!, do we need to worry about no PS made? we aren't doing anything like V&A's. we were going to just wing it!
I think, as long as you are willing to wait, you will be able to get a table at mostly anywhere. Also, if you are flexible with your meal times, that is a huge help as far as wait time. Without kids, you can eat an early or late dinner, etc.
Kimwim is right, but the key phrase is, "as long as you're willing to wait." May is the start of busy season, so you may have a very long wait at the nicer restaurants. If there is anywhere you really want to eat, my advice is to make the PS.
Personally, I would make at least one PS for your anniversary night. Those waiting areas get really crowded with hungry, impatient people. You can always make PS from your hotel the morning of.
If you really don't want to make PSs, I would suggest eating after 8:30.