Is there any harm in safeguard?

[Steve_Mudge]

When using events and the Invoke(), is there any harm in safeguarding it with the ‘?’

onHit?.Invoke();

Does it cost more performance ?

[Brian_Trotter]

I use it everywhere.
This is what is called null propogation, a form of syntactic sugar. The compiler actually expands this to

if(onHit!=null)
{
    onHit();
}

What this means is that you don’t need to surround onHit?.Invoke(); with a null checking block.