If I have a single if condition I wouldnt spend too much time ruminating about the style. But if I have multiple guard conditions I would prefer style2

Picuture this. Assume that the tests are complex and you really dont want to tie them into a single if-ORed condition to avoid complexity:

//Style1
if (this1 != Right)
{ 
    return;
}
else if(this2 != right2)
{
    return;
}
else if(this3 != right2)
{
    return;
}
else
{
    //everything is right
    //do something
    return;
}

versus

//Style 2
if (this1 != Right)
{ 
   return;
}
if(this2 != right2)
{
    return;
}
if(this3 != right2)
{
    return;
}


//everything is right
//do something
return;

Here there are two main advantages

1. You are separating the code in a single function into two visually logcal blocks : an upper block of validations(guard conditions) and a lower block of runnable code.

2. If you have to add/remove one condition , you reduce your chances of messing up the entire if-elseif-else ladder.

Another minor advantage is you have one less set of braces to care for.

If I have a single if condition I wouldnt spend too much time ruminating about the style. But if I have multiple guard conditions I would prefer style2

Picuture this. Assume that the tests are complex and you really dont want to tie them into a single if-ORed condition to avoid complexity:

//Style1
if (this1 != Right)
{ 
    return;
}
else if(this2 != right2)
{
    return;
}
else if(this3 != right2)
{
    return;
}
else
{
    //everything is right
    //do something
    return;
}

versus

//Style 2
if (this1 != Right)
{ 
   return;
}
if(this2 != right2)
{
    return;
}
if(this3 != right2)
{
    return;
}


//everything is right
//do something
return;

Here there are two main advantages

1. You are separating the code in a single function into two visually logcal blocks : an upper block of validations(guard conditions) and a lower block of runnable code.

2. If you have to add/remove one condition , you reduce your chances of messing up the entire if-elseif-else ladder.

Another minor advantage is you have one fewer set of braces to care for.