I hate signing up early, Sod’s law means I’ll catch a cold or fall off my bike the day before. So far this year:
Duathlon – signed up 1h before the start
Local X-C MTB champs – signed up 1h beofre the start
Ski mountaineerign race – didn’t sign up as it was cancelled due to dangerous conditions by sign up time
Ski Mountaineering race – signed up three days before (or a team mate did)
Winter triathlon – signed up three days before (1h before deadline)
Winter triathlon – signed up a week before and about four days before the deadline (my main objective for the year)