It is, of course, possible to make decent cheese without thermometres, hygrometers, and pH meters and such, but if you have them it can speed up the learning curve a great deal. Being able to measure what's going on enables you to compare the feel and other sensory information when it's reached the desired target. Some cheeses are fairly forgiving, others, not so (my recently binned stiltonesque, for example). More equipment won't make up for bad technique, by which I mean knowing that you've shot past your temperature and/or pH targets doesn't change the fact that you have, but it does let you know where you need to be more careful in the future. Other things come with practice, such as figuring out what "gentle" means when stirring.