As with Adventuredon, I have two sleeping bags, one light and one three season. In my world, it’s a bit like having a different clothes (or at least different layers) for different weather. Both bags I have had for years. The trick is to look after them. I air mine fully on return and leave it put away in a simple mesh bag, not squashed into a tiny compression sack. If they ever need washing, I follow the very simple instructions on the label, nothing more. I think the lighter bag must now be 20 or more years old and near enough as good as the day I bought it.
My air bed, is the Exped Downmat 9LW, which I cannot recommend enough. If I am going by car, I might take a proper camp bed but on the bike I find the air bed is more than adequate.
If it’s going to be steaming hot, I have a silk liner, which weighs and packs down to nothing. If it’s going to be cold or wet, I have an ex-army gore-tex cover, bought secondhand of UKGse years ago. It simply traps are between my sleeping bag and the outside air, which warms up. Again, horses for courses…. Just look after it all.