Depending on your home and how many motorised curtains you have this can vary. For separate rooms, like bedrooms that have one motorised curtain, we'd recommend a one channel remote. For common areas, such as a living area with multiple motorised curtains, we'd recommend a five channel remote.
We always recommend you buy a remote with your motorised curtains, even if you're planning to use your smart phone or voice to control your curtains. It's handy for guests in your home and for initial set up.