A new mattress can be really tall, making it feel like you are climbing a mountain to get into bed. That’s why good manufacturers ( like Charles P. Rogers) offer 2 options on the height of your foundation at no difference in price or performance; Low Profile or Regular Height.
Why Get A New Foundation - Your new mattress, a significant investment, needs proper support. Many folks consider using their existing foundation rather than buying a new matching foundation: it’s seen like an add on rather than a necessary purchase. But ask yourself, why you are replacing the mattress? Poor comfort & support? Valleys & depressions? Your foundation could be as worn as your mattress, it wont give your new mattress proper support, nor proper alignment for you and your partner. Your brand new mattress might break down even more quickly than you’d like.