Short question: is it worth the effort to overhaul the bottom bracket of an old (1986) Azuki road bike, or leave well enough alone?

Context:

Three years ago I bought a used road bike off craigslist. I believe it to be a 1986 Azuki Imperial, with what seems to be orginal components and parts. I swapped out the 5 speed freewheel for a 6 speed (also a Suntour freewheel), and have changed the small chain ring to a 36 for some extra help on hills. It has held up well, and I have really enjoyed riding it.

This winter, I am trying my hand at some maintenance. I am replacing both the brake and gear cables (both a bit frayed), swapping in some aero brake levers, and putting in a longer stem (the orginal was 50mm, a bit short for me).

I have taken everything (except the cranks) off of the frame to clean it up. I bought a cone wrench, and have just starting to overhaul the front hub. So far so good.

Now I am questioning if I should go ahead and deal with the bottom bracket. It spins smoothly, no bumps, clunks, or issues. Although, if I strain my ears, it does sound like there is some grating inside when I turn the cranks, like a tiny bit of sand or something. Then again, it could be my hearing.

In order to open up the bottom bracket, I would have to buy a crank puller tool, along with the necessary wrench to open up the bottom bracket. I could also take it into a LBS and ask them to overhaul the bottom bracket, but I am really trying to minimize any further expense (what do we call buying N+1 tool?)

Or should I just do the maintenance I had planned, put everything back together, and ride it until I feel there is really something wrong?

Thoughtful advice appreciated.