I have a pair of profile design aero bars I fit for both TTs and anything over 100 miles. They were a godsend on my double century last year. It was nice having another position to be in, and allowed me to stretch my back out a bit while still on the bike. As mentioned above, if you have smaller width handlebars, real estate does become an issue. Mine are 36cm, but profile design make an attachment that gives you a mounting a point between the aero bars that I use for lights. I've opted to keep my wahoo bolt on it's stem mount, instead of it's out front mount. I do TTs for a bit of fun, not competitively, and having it on the stem mount allows me to charge it on long rides if needed.