You recycle, ride a bike to work, and buy organic food. You pay extra for "green" electricity and have an eco-friendly car. So can you rest easy, with a clean conscience that your life is as sustainable as it can reasonably be?

Well … although many of us try our best to minimize environmental impacts, our actions don't always achieve as much as we believe.

Expensive products that are marketed as eco-friendly may help us to assuage our guilt while drawing our attention away from the more pressing issues.

Meanwhile, other actions and products can be useful, but only when used as part of a wider environmentally aware lifestyle. Most worrying of all, some things marketed as sustainable can have negative side effects for the environment—that's called greenwashing.

The Green Guide talked to several sustainability experts who highlighted five eco-strategies and products that may not be all they are hyped up to be.

For the busy executive and the hassled family alike, carbon credits seem like a simple way of negating the environmental damage without making significant changes to your lifestyle.

Hop on a flight from the U.S. to Europe and you can pay a carbon offsetting company a fee to mop up your greenhouse gas emissions, for instance by planting some trees or installing solar panels in a developing country.

But can we really continue to take exotic holidays and still have a green conscience? Many sustainability experts think not.

(Related story: "Do Carbon Offsets Do More Damage Than Good?")

"Carbon offsetting is a con—it encourages businesses and individuals to carry on polluting when we urgently need to reduce our carbon emissions," said Andy Atkins, executive director of Friends of the Earth U.K.

"It's not enough to make emissions cuts in developing countries. Rich countries have got to lead on tackling climate change by reducing their own emissions," Atkins said.

(Get green-travel tips.) Furthermore, it isn't clear that all carbon credit schemes really do lower greenhouse gas emissions, experts say.

"The science behind some of these schemes is still not clear," said Wouter Buytaert, an environmental scientist at Imperial College in London, U.K.

For example planting fast growing pine trees on grassland will lock up carbon in the tree—but may also disrupt the soil and release large amounts of carbon stored in the grassland.

That's why "staycations," or taking vacations at or near home, are the deep green option, many experts agree. (Read about "extreme staycations" on the Intelligent Travel blog.)

"The greenest thing holidaymakers can do is choose a location that is closer to home, that can be reached by coach or by train," Friends of the Earth's Atkins said.

"Governments must ensure rail is a fast, convenient, and affordable alternative to flying," he said. However, some scientists argue that carbon credits aren't all bad. "They are a worthwhile option when you have done everything else possible to reduce your emissions," said Dave Reay, an environmental scientist at Edinburgh University, U.K.

And carbon credits do at least draw attention to the problem.

"The concept isn't great, but they are a good way to force a transition," said Andy Kunz, director of the U.S.-based New Urbanism, which works to promote walkable neighborhoods.

Is it time to trade it in the gas-guzzler for a more fuel-efficient model?

When it comes to cars, the fuel efficiency needs to weighed against the "embodied energy," or the energy used in making the car, experts say.

That means taking into account how much energy was used to refine the iron ore to make the steel, then the fuel used to ship the steel to the car factory, and finally the energy used to assemble the car and transport it to the showroom.

In their book Time to Eat the Dog?: The Real Guide to Sustainable Living, authors Robert and Brenda Vale calculate the embodied energy for four different types of car: the Smart Fortwo, the Volkswagen Golf, the Holden Commodore, and the Toyota Land Cruiser.

energy—the Toyota Landcruiser consumed more than three times as much energy as the Smart Fortwo before either car even hits the road.

The authors also calculated the fuel consumption for each car for an average lifetime of 149,129 miles (240,000 kilometers.) For all four cars, the energy attributed to fuel consumption was around five times the embodied energy by the end of the car's life.

These calculations reveal that buying a new car might be beneficial for the environment, but that it depends on the fuel consumption of your existing car and what you intend to replace it with.

"If you replace your SUV with a Toyota Prius, it is worth it, but if your old car is a Morris Minor [a small British car popular in the mid-1900s] and you replace it with a Range Rover, it is not worth it," said Robert Vale, an architect at Victoria University of Wellington, New Zealand.

Changing your driving habits can really help to save fuel. "Driving smoothly, getting rid of unnecessary weight, and keeping tires inflated can cut emissions by up to 30 percent," said Friends of the Earth's Atkins.

"But the best way to cut emissions from cars is to use them less."