Are Dumbbells Enough?

Like many people, my main resolution for 2014 relates to strength. I want to build my strength. When I say I want to build my strength, I am referring not only to a strong mindset, that is, assertiveness and my ability to say no and to stand up for myself, but I am also referring to my physical strength. As a result, late last year, I told myself that I would join a gym. I am now having second thoughts. I've been googling, and many articles recommend that I be wary about gym contracts locking me in. I also don't know how easy it is for me to commit to going to the gym.

It's not that I don't do any workout at the moment. I currently use 5 kg dumbbells at home that I do use, and they are great in terms of convenience because I can work out at home and save on gym membership fees. But 5 kg may not be enough. The workout is starting to get easy, so perhaps the next step is to progress from the 5 kg dumbbell to the 10 kg dumbbell. My plan is to buy online to get the best price.

Are far as technique goes, there is plenty of guidance on the internet on how to use dumbbells. Some people argue that strength training is not enough, that you need to engage in cardio workout, for example, running or swimming, but my counterargument is that, if you lessen the weights, for example, if you use 2.5 kg dumbbells, and workout for a longer duration (higher reps) then you effectively get a cardio workout. It helps if your dumbbell sets vary in size or are adjustable.

Currently I do not have a bench but will see if I can use my 10 kg dumbbells without a bench. I do my workout in my bedroom where there is not much space, so it would be ideal if I can avoid using a bench. Once 10 kg dumbbells get easy, I'll consider using heavier weights.