If you are a regular scuba diver you probably want to invest in a scuba diving computer. The primary purpose of dive computers in recreational diving is to tell you when you near or reach a no stop limit. If you exceed a no stop limit, most dive computers show you the depth of your first decompression stop and the decompression time.
On top of this almost all dive computers today have functionality to display current depth, elapsed bottom time and ascent rate, and some computers show current water temperature as well.
Here are some steps to help you along your way to choose the best dive computer for your needs. First, answer these questions for yourself:
1) Do you want to use the computer for free diving as well as for scuba diving?
2) Do the environment you will be scuba diving in require a compass?
3) Do you, or do you plan to, dive with nitrox?
4) Will you be scuba diving at an altitude? (Lake diving above sea level)
If you answer no the the questions 1 & 2 above any model of dive computer will be enough for your needs, and the only thing left is to decide based on price and look. Here in Dahab a new scuba diving computer for beginners costs about 125 euro in the store (mostly Suunto Zoop), but you should at least not pay more then 250 euro for your scuba diving computer in this class. Don’t forget to check if the model you choose have support for nitrox or altitude diving, if you answered yes to those questions.
If you answered yes to question 1 or 2 above the price for your scuba diving computer will be a bit more expensive, probably around 300-450 euro. In this category you can also choose to have information about the current tank pressure and time left of your air supply (if you continue at the same breathing rate and depth).
The above information is only for normal recreational scuba diving. If you plan to do tech diving or commercial diving you will need a more advanced scuba diving computer.