I'm looking for some general advice on how long a dairy free/egg free cake will last for a customer please? 

I used a recipe substituting dairy and eggs with soya milk and oil and I'm really happy with the bake- it's very moist and tastes really nice! With the buttercream I used a dairy free butter too. 

I just cannot find find anywhere about how long this will last- As the cake is heavily decorated I've made on Thursday for the party on Saturday- It's a stacked caked so covered in fondant and decorated on top- will this be okay into next week? 

Will this last the same as a normal sponge cake? As it's all protected with fondant? 

Any would be greatly appreciated! 

Thank you!!!