There are many factors to consider when replacing a monumental skylight.
The first is cost, of course. Large monumental skylight costs are hard to put into a maintenance budget for any company. Costs vary upon the type of skylight that is needed.
Second factor to look at is the actual process of replacing the skylight. Most companies don’t want to shut down while the replacement is being completed, but it is difficult to remove one skylight while at the same time installing another. (See Shopping Center Repairs) Also, safety for the public cannot be compromised.
Third factor is design and planning. Design of the skylight, including any changes that might be required of the existing support structure; preliminary budget bids, and finalizing plans with all the approved stamps can take just as much time as it takes to get the skylight made. Ordering time depends upon each manufacturer and the time of year but typically takes 8 to 12 weeks. Changing the amount of light, either more or less, is also critical and should be considered during the design phase.
The fourth factor is the time of year the installation is scheduled. Many companies get through the design and planning process by mid-summer and then want to order their skylight. The delivery of the skylight may not come until late fall or winter and that may be a problem with the weather, depending upon your local weather conditions. You may have to put off the project until the following year, which does nothing for the continuing leaks.
However, if you are willing to navigate through all of the above decisions and time lines, then you do get a brand new skylight. Advantages to this are several: you may get an entirely new design, you probably will get new design technology, you will get a new warranty; length of time depending upon the manufacturer and/or installer.
One more item to note. Never let a roofer work on your new skylight that is not a commercial skylight specialist. It is the quickest way to ruin a perfectly good skylight.