Individuals that wear contacts may be able to wear them for a long time if they are used properly. People that do this will usually get replacement lens when they are near the end of their original sets. Other people that wear contact lenses may have a different view. These groups are usually composed of people that buy replacement lens in bulk.
There are two reasons why a person may decide to have a large supply of replacement lens. The first reason is because they do not use one set of contact lenses very long. It may be because they lose them or because they like to replace them often. People that do this may need to have a constant supply available.
The other individuals that have a need for abundant amounts of the replacement lens are those that wear different colors. An individual that has access to multiple colored lenses may sporadically decide that they want to wear another color. The replacement lens can be crucial for people that change their contacts frequently.
So much of this depends on cost and the ability to find a good supplier. Lots of websites have discounted prices for people that need to purchase contacts. It may be difficult to decide on a specific vendor, however, if no orders have ever been placed before. Most customers choose to stick with their original suppliers for this reason.
Many of bundled packs come in 6 month supplies. Some individuals may take their chances with last minute orders, but money is actually saved for the bundled supply packs. Some of these packs come with the timers that indicate when it is time to order more. This is helpful once users get into a cycle. This helps them discover how much they should buy in the future.