Most experienced bike riders are scared of getting a frame too big, because they associate it with looking like a newcomer. Most riders have the tops of the bars where the drops are supposed to be, and the drops are down there so far they never get to them. The stem angle is too low. The frame is too small. In other words, buy the biggest bike you can straddle with an inch of clearance between the top tube and pubic bone .
Handlebars can be too high.
If you climb a lot of hills off the saddle and holding the brake hoods, you need to be able to completely relax and nearly straighten out your arms as the bike rocks side to side. But if the bars are too high your arms won't extend and relax, and your biceps will get tired from being flexed all the time. On the other hand, if you don't climb hills off the saddle, you won't mind the bars way up there. Usually people raise the bars as a last resort to fix an aching back, but I think 95 percent of all riders can benefit from higher bars, and that includes fast people. If you're time trialing with your back nearly horizontal, hands on the drops, look at your lower arm.