I also like to dig through the backlog when doing a major refactor or a large feature. I'll look for related things that might help inform the design.
It's surprising how often you find cases where we couldn't do A, because it depended on B which we didn't have back then and it would have been too much work to do B just to get A, so A just gets backlogged. But now that B is finally getting funded, if we do B right, we can let A come along for the ride almost for free. Then a whole bunch of related things like that can get cleared from the backlog all in one fell swoop.
The other time it's good to dip into the backlog is when the problem has become more serious due to shifts in usage patterns meaning the impact now justifies the work when it may have been borderline before.
It's surprising how often you find cases where we couldn't do A, because it depended on B which we didn't have back then and it would have been too much work to do B just to get A, so A just gets backlogged. But now that B is finally getting funded, if we do B right, we can let A come along for the ride almost for free. Then a whole bunch of related things like that can get cleared from the backlog all in one fell swoop.