Tip of the day: Use more local variables
Using local variables to cache values you query often can speed up an app a lot. For example in a web app, if you use a loop of code and you access the current session with the session function, you waste a lot of time. Just an example:
for i as integer = 1 to 1000
Session.t.test
next
Session.t.test
next
and this code is 10 times faster:
dim t as test = Session.t
for i as integer = 1 to 1000
t.test
next
for i as integer = 1 to 1000
t.test
next
Same applies for arrays where it's often better to lookup the value once in a loop.
Debugging
Another reason for local variables can be to see them in the debugger. For the runtime speed of your app it doesn't really matter if a value is stored locally. In a lot of projects I have code like this:
dim db as database = Session.db
So I can see the local properties of the database right there in debugger.