Tables used to be the standard. At this point, nearly all recreational divers wear a personal dive computer and it makes sense.
Your computer monitors your depth, time, speed of ascent, and NDL in real time. Tables give you a static plan. When you go shallower during a dive, a computer adjusts. A table can't.
Wrist-mount computers are the most common go for at this point. These are compact, readable underwater, and you'll wear them as a watch too. Hose-mounted models are still around but less divers pick them these days.
Budget computers start around $300-odd and do everything the average diver requires. You get depth tracking, bottom time, no-deco limits, a logbook, and often a basic freediving mode. Stepping up to mid-range gets you transmitter compatibility, nicer displays, and extra gas compatibility.
What buyers don't think about is conservatism settings. Some algorithms are more conservative than others. A tighter setting means less bottom time. Looser ones extend bottom time but with less buffer. It's not right or wrong. visit this It's your style and how experienced you are.
Check with someone at a local dive store who's used multiple computers first. Staff will offer a straight answer on what works versus what's just marketing. Decent dive shops have gear reviews and comparisons on their sites as well