Tables used to be how everyone dived. These days, most divers dive with a personal dive computer and it makes sense.
A dive computer calculates depth, bottom time, ascent rate, and NDL in real-time. Dive tables are a fixed calculation. When you move between depths during a dive, it updates. Tables are set before you get in.
Wrist computers are the most common use now. They're small enough, readable underwater, and you can wear them as a daily watch as well. Console computers are still around but fewer buyers pick them these days.
Entry-level computers go for around a few hundred dollars and cover everything a recreational diver would need. Features include depth tracking, dive time, no-deco limits, log function, and often a simple freediving mode. The $500-800 range gets you wireless air monitoring, better screens, and extra nitrox options.
The one thing buyers overlook is algorithm differences. Certain algorithms are tighter than others. A conservative setting results in reduced bottom time. More aggressive settings give more time but at reduced buffer. Both work. It just personal preference and experience level.
Check with people at a Cairns dive shop who's used multiple brands first. They'll offer honest opinions on which ones hold up and what isn't just marketing. Most good dive stores publish gear reviews and rundowns on their further reading sites as well