I am pretty obsessive about reading series in order, even if just loosely connected. I am up to the 3rd in the slightly series called Slightly married. I count One night for love as 1st and A summer to remember as the second.
I did read for some reason Simply love without reading the ones before and then found out that the Slightly series also comes before the simply. No wonder I keep printouts of authors like Mary Balogh that wrote like rabbits

I actually keep a spreadsheet of all books read sorted by author and with the series name and number next to the title. I print it form time to time. It helps me keep up with all the series. For some reason especially in Historical romance there are a lot of series and connecting stories going on. Then you add how prolific some of those authors are and you need a flow chart to keep up

Its so bad I can't just pick up a book and go, oh maybe I'll read this now. Oh no, I have to go to fantastic fiction first to see if its in a series, or connected, or any other reason I need to read something else first

I hate that some authors have switched away from Historicals to like contempo and suspense. Julie Garwood is one such tragedy. She had some great heroines. Heroes too. And since I don't like much contempo stuff its a big loss to me when they switch.