Stripper or strictly sanding: which is better to refinish old wood?

Unless the wood is veneer, both should work, although the stripper won't boo-boo and sand off too much and make it uneven. Neither one should weaken the wood. My father refinished antiques all the time and used stripper and they came out fantastic!

citri strip is a decent stripper agent. The pluse for my nose is that it doesn’t smell as bad as others. You will need a tool the scrape the the stripper agent and goo off the bookcase. When its off you will need to clean the wood. Water will raise the graining, you can use rubbing alcohol on a lint free cloth. Examine the piece for damaged areas and repair. Then choose to either stain and varnish, or prime and paint

You may to give it a light sanding before the new finish goes on. Get the sanding dust off before your finish coats. Okay Freddy grey wants his dinner...

I hand sanded my trunks which were filthy ( sounds ominous Ha) but was the best result , then applied Bry Wax. So lovely with good shine. Also did this indoors as weather does not permit outside work most of the time. Electric sanders are messy and corners are tricky.

The major reason for stripping it is the possibility of lead paint being present. If you sand it the paint particles go air born...and can be inhaled and cause a few issues.