64-bit: Do I Need to Use the 64-bit Solaris Application Environment?

No, unless you are developing 64-bit applications on a 32-bit or 64-bit Solaris 7 system or running 64-bit applications on UltraSPARC systems.

Although running 64-bit applications can have enormous advantages over running some 32-bit applications--particularly applications which are able to manipulate large address spaces, such as databases--the 32-bit Solaris application environment will continue to be the default application environment for a long time to come.