Things go down without notice all the time and they really have no control over it (such as ToT being down for almost a week recently). If something is noticed, during the daily checks, that could possibly be a hazard or cause an issue with the ride then they have to shut it down and sometimes they have no way of knowing how long something will be down for. Especially with all the different things they have going on. Spring is common for refurbs anyway because it's off season. When I was planning vacations I would never go during the first part of the year because there are always more closures at that time than any other time.