It depends on what you and your partner want and define as your family unit. Most conflict in any relationship comes from un met expectations.
For us that means we have three children in our family unit. One each and one together.
I do consider my SS when out shopping or now his child my step grandchild for example. As does DH.
He is much better at it than me and manages pretty much all their birthdays and Christmas. He has a note in his phone that he writes down things throughout the year all of them mention. Be it things they want to do or presents they might like.
We have such large ages gaps there is natural differences in their day to day life. But our older children had what dd has. Access to activities, days out holidays etc.
We do things altogether and seperately. Due to the age difference our youngest does days out etc that the older ones won't always want to do. We do things with the older ones that aren't appropriate for the younger one.
Our inheritance is split equally because with out each other we wouldn't have the amount of income and assets we do. Each of our children has benefited from us being married and combining our income and assets.
For big life and family decisions over the years DH and I sit down and discuss the impact it might have on each of them.
They don't all get the same but they all get what they need from us like in most families.
For example help with driving lessons and cars will be equal. One of ours is going to college so is getting help with that. One didn't and went straight to work.
Buying a house for example we will give them all financial contributions.
We don't do conflict over them generally and do don't do competition as in your child versus mine. It's easy to fall into and when we felt our selves going that way in the early years we stopped. We can't control what happens outside our home only what we bring to each of their lifes.
If I'm being truly honest reading the SP board I feel there are many poster that have at minimum a low level unhappiness with their life and resentment for being in a relationship that involves step children. It's a situation that is tolerated.
That's isnt something dh and I wanted for any of them. Both of us had other relationships with partners that didn't have their own children and it was much more difficult. We both felt much more of a them and us with our partner and child.
We don't have that in our marriage now.