When to move your product to 64 bit architecture

i was working on a project where the tools developed by my team has to work both in x86 and x64 platforms. One of the reasons of building for 64 bit application was to not be missed from selling our product in 64 bit platform. But we looked in to other reasons too. They are

One is the amount of memory that the application can have. 64-bit computing is all about handling more amount of data in memory than 32-bit systems. This would make data access and processing more effective as this results in fewer input/output read/writes to disk subsystems, which are significantly slower than direct access to memory.To be more precise, in process in 32 bit computing, 4GB of data can be kept in memory, but with 64 bit computing, you can reach very large(is it 16 exabytes.?)

If your 32-bit application is constantly running out of memory — or that would benefit from having access to large amounts of data stored directly in closely resident memory — 64-bit computing should be considered. A note of caution is make sure that device drivers that are needled by your application are compatible with 64 bit platform.

But my company did not allow migration my laptop to x64 due to the cost and i need not handle application using large amount of memory, me no being a Project Manager.