I was handed a pocket New Testament with Psalms and Proverbs today, and it got me thinking about if not including the Old Testament is wrong. The whole Bible is the word of God, and while I know the intent of the publisher and the person who gave it to me is good, I wonder if omitting part of the Bible is problematic. Admittedly, I have a very severe clinical obsessive compulsive problem, so I may be overthinking this. Thoughts?
I think you are overthinking it. If you have a complete Bible at home, and you use it, I think you are fine also using a pocket New Testament. Having the Psalms too, the prayerbook of the Church, is good, and that part should not be overlooked in your reading.
Pope Francis recommends it. But sometimes he says 'Bible', sometimes 'New Testament', sometimes 'Gospels'. I think his point is to read, particularly the words of Jesus. If a pocket Bible helps you do that, on the bus or wherever, that's probably good.
There are pocket Gospels and Acts, pocket New Testaments, pocket New Testaments with Psalms, and whole pocket Bibles. The latter end up having VERY TINY PRINT.
For a while I had a pocket NT and used it a lot. It was an old WWII Confraternity version New Testament issued to soldiers by the chaplaincy. I found it at a used book store for cheap. It finally wore out entirely and I never did get it replaced. It was like 3x5 inches and 3/4 inch thick. Very portable. I am probably finally going to get it replaced this year.
Here is another idea, perhaps a parallel one. Find a spoken Bible, one that fits with your phone or tablet, that you can listen to in your car or on walks.