I'd agree analog gauges are the best option. I started off with a digital one.. it was quite a cheap model but I check my tires regularly (at least once a month) and I ended up spending more on batteries than the gauge cost! Go for analogue with a large dial, mine has lasted for 8 years and...
Absolutely, dont go higher than approx 60 psi for normal car tires. It seems the industry standard is 2%, which i think is sufficient. The variation due to the heat of tires during use will vary the pressure more than that.