What age gap between kids do you think is right?

My son is 10 months old and I always thought I wanted 2-3 years between my kids. I think I want 3 in total. But now he's nearly one for a 2 year age gap I would need to try soon and I'm definitely not ready to be pregnant or have another new born. I feel my son needs my undivided time for a while yet. I now think I would maybe try just after he turns 2 but what if it takes a while for me to fall pregnant and there's a 4 or more year age gap. I really don't know what's best. I think 3 years is best due to childcare costs etc.