That's all up to you.
But here's what I don't recommend.
You select all our shots in colour, and tell yourself, "No worries. If I want any in black & white, I'll just order them like that from the Photo Lab."
Don't do it.
And here's why.
This is a shot I've edited in full colour (yummy baby, by the way):
If you order it in colour only and then check the "black & white" box while ordering your shots from your Photo Lab, you can end up with something like this:
Besides the fact that this is no longer representative of the quality of the work I did for you, you may as well have left it in colour. You deserve better than this. The image is flat and has been robbed of much of its warmth and character.
Here is what I would have given you:
I spend time adjusting sharpness, shadows, highlights, clarity, and even blur on each of my custom-processed monochrome images. It's time well spent, and the end result is worth it. Not to mention, if you order an image that doesn't translate into monochrome very well, I'll recommend another option.
(Oh, and while we're at it, please pretend the "sepia" option on your camera and at your Photo Lab don't even exist. Unless you're shooting a western, of course.)
There you have it. Thought you just might like to know.
I'll be making adjustments to my List of Services in the next couple of weeks, and you'll note a special twist on how I offer monochrome images.