While a spring mattress was the standard for many decades, foam mattresses are becoming more and more popular due to their unsurpassed comfort and overall body support. While spring mattresses can feel nice to sit or lie on, they will not offer anywhere close to the body contouring, and therefore spinal support, that memory or latex foam can offer. There is always fiber and some type of foam over the springs, but these coils will actually cause a trampoline effect and bend inward when pressure is applied without conforming to the specific bumps and curves of the body. While foam can shrink over time, springs can bend and lose their shape over time. Therefore, an old foam bed will likely feel better and offer better support than an old spring mattress.