Beirut is a walking city until it suddenly isn't, and the difference usually comes down to where you decided to sleep.
The Neighborhood Problem
Ask five people where to stay in Beirut and you will get five different answers, mostly because the city does not have one obvious center. Gemmayze has the bars and the old stone stairways. Downtown has the reconstructed souks and the mosque-and-cathedral skyline. The waterfront near Zaitunay Bay has the yachts and the seafood. Picking wrong means a taxi ride every single evening.
What Actually Matters
A good boutique hotel in Beirut solves the neighborhood problem before it starts, by sitting close enough to two or three of these districts that walking becomes the default instead of the exception. Staff who know the informal taxi and service-car system matter almost as much as location, since Beirut's ride apps do not cover everything a visitor needs.
Timing
Book further ahead than feels necessary during festival season or major conference weeks. The well-located rooms disappear first, and what is left tends to be the properties that required that extra taxi ride in the first place.