My previous two cats lived to 17 and 20. As they aged I looked for a ramp they could use to get into their (i.e. my!) bed but couldn't find anything quite right.
Now I have two younger cats. They don't need the ramp yet, but this looked perfect and it was on sale, so I bought the larger one. One cat likes to scratch on it (I "seasoned" it with catnip). The other cat isn't as enthusiastic, but she'll climb to the top to get treats, and with time she'll be fine.
This ramp is a bit expensive, ...