Hi Guys,
I you are going away for 12 months then the sand and varnish option is best. Oil and wax are a OK option but needs redoing regularly to stop the timber deteriorating to a state where the cupboard needs replacing.
If you sand it make sure to sand with the grain not across it. Be careful if you chose poly urethane as it is toxic and takes a few days to dry. Once dry it is hard wearing.
I would use quality varnish
When I was a cabinet maker, we used a matt finish for first few coats and then finished with a high gloss to give it a lot of depth. In between each coat give it a light rub over with steel wool to give a better finish.