Pretty much anyone I knew doing architectural work always refrained from correcting to the perfectly correct (a photographer's concept, anyway), which is inevitably the wrong way to go about it. A picture has to look real. Desert that maxim, and you fall into comedy. It might be crisp as hell, parallel as hell, but then it will also look like hell.
A grid screen is a great aid in judging when to stop, but on small cameras it ain't at its best, and almost useless other than for lining up horizons if you shoot at the seaside a lot.