The VBA compiler doesnt care about the capitalization style of your variable names. MyVar,
myVar, and myvar are identical names as far as the compiler is concerned. (If youre inconsistent
about the capitalization of a variable name, the VBE adjusts all instances of that variable
to make them look the same.)
If you change the spelling of a variable name in mid-program,
however, the compiler creates a new variableand havoc for your program. An error in
programming introduced by a misspelled variable can be especially treacherous because the
program might appear to behave normally.
You can virtually eliminate the possibility of inconsistently spelled variable names in a
module by adding a single statement at the top of that module (above any Sub or Function
statements):
Option Explicit
The Option Explicit statement forces you to declare any variables used in the current module.
You declare variables with Dim statements. (For the complete details about Dim, type Dim in
a module and press F1.) With Option Explicit in place, if you use a variable without first
declaring it, you get a Compile Error at run time. If you accidentally misspell a variable name
somewhere in your program, the misspelled variable will be flagged by the compiler as an
undeclared variable, and you will be able to fix the problem forthwith.