Speed is the essence with aptitude tests
Often in an aptitude test it is not the nature of the questions themselves that cause people to struggle, but rather the time limits imposed on the candidates taking part in the assessment.
So, if you are preparing to sit a psychometric test, it can really pay off to practice your speed. If you had all day to note down your responses to the challenges posed, you may well make very few mistakes. But the reality is that with your back against the wall and time running out, you might well find your logic deserts you and you fail to show your true abilities.
This is why it can pay off to practise such questions in advance of the real test. This enables you to get a feel for the pace of the trial and to adjust your approach accordingly.
There is a distinct skill to spending enough but not too much time reading each question. If you rush this, you will make lots of mistakes on your aptitude test. In contrast, if you re-read sentences again and again and are too slow in your progress, you will fail get through the assessment. By practising them, you can get a feel for how speedily you should go through the trial.
Another great thing about preparing for a psychometric test is that you become more familiar with the type of wording they use. This means you will be more efficient in your dissemination of the questions than someone who has not looked as other such papers before.