A full set of diving gear is a considerable investment that not everyone is ready to make, especially if one plans to buy an entire set at once. The next option is to buy gear one piece at a time and rent the rest, but then there is a question about what to buy first. One answer is to prioritize purchases based on what piece of gear offers the most value. In this article we'll consider each of the basic components of a scuba unit with regard to their cost versus their benefit. The components are listed in order from highest "return on investment" to lowest. Hopefully this discussion will give the reader some guidance on what scuba equipment to buy and what to rent.

First, let's define "cost" and "benefit". Cost is, of course, the money needed to buy, use and maintain the equipment. Safety, performance and comfort are considered benefits, since they are the primary requirements for any piece of scuba equipment. Other benefits will include versatility and convenience.

Skin diving gear
Mask, fins and snorkel are considered to be basic equipment that every diver should own. Their cost is relatively low and the benefits are high. Most professional skin diving equipment will perform well and is versatile enough to be used for most types of diving from snorkelling to technical diving. The mask, fins and snorkel should be comfortable and convenient, especially the mask. Ill-fitting skin diving equipment can severely impair a diver's comfort and safety underwater. Importantly, dive stores may not carry a big enough selection of rental gear to allow any one diver to find equipment that fits.

Timing devices
For several reasons, it is often advisable to make a watch or other bottom timer a first purchase. There are many inexpensive timers available on the market and most are safe, comfortable and perform well. In this case, a high return on investment is the result of the low cost. Note that for this discussion, dive computers are considered to be accessories, because they are recommended for use as secondary, not primary timing devices.

An exposure suit
Wetsuits and drysuits offer a very high return on investment because of the comfort, performance and safety they provide. Suits vary in price and it is quite feesible that an inexpensive suit will perform very well. A new suit that fits properly and is appropriate for the type of diving done should make the diver more comfortable and may offer protection from abrasions, cuts and stings. A suit that does not fit can ruin a dive by failing to provide warmth, confining movement and even constricting circulation. In addition, rental suits tend to have a characteristic odor that can be most unpleasant.

BCDs
The BCD is a core piece of a diver's life support system, and as a result many divers feel more comfortable using their own, even though most BCDs are designed to be fail-safe. In this case, the cost is high; BCDs expensive to buy and annual service makes the cost even higher if parts and/or service required for overhaul are not covered under warranty.

Regulators
Basically the same discussion applies to the regulator (primary, secondary and gauges) as to the BCD. The main difference for the sake of this discussion is that regulators are usually more expensive to buy than BCDs, so the return on investment is slightly lower. In summary, BCDs and regulators are both highly desirable to buy, but generally safe and more affordable to rent if not needed frequently.

Tanks
Unless an individual dives frequently (more than twice a month) or prefers to dive with high pressure tanks, tanks do not offer a high return on investment. In fact, after calculating the cost of air fills and maintenance, simple math will often reveal that renting tanks is a cheaper way to go. Additionally, the inconvenience of storing and transporting such bulky gear makes renting a better option.

Weights
There are relatively fewer advantages to buying weights versus renting them. Rental weights don't differ significantly in performance and are only slightly less convenient to transport. The decision whether or not to buy weights really depends on two things. First, if a diver uses weights enough to justify the cost of purchase. Second, a diver should buy weights based on any strong personal preference for a particular weight system as opposed to relying on dive shops to rent their favorite kind.

Accessories
At the end of our list, we include diving accessories. There are hundreds of different accessories offered in the marketplace, all of which vary in cost, degree of usefulness, safety and performance. Some examples include dive knives, lights, computers, slates, redundant air sources and fasteners. These should be evaluated on a case by case basis and used only if required to make a diving more safe, comfortable or convenient.

In closing, buying equipment one piece at a time is advantageous in many ways. Not only does it make diving more affordable, but it gives the inexperienced diver a chance to experiment with different types of rented or borrowed gear and can result in more experience with different equipment offerings and their own personal diving needs.