Sealing Grout in Shower

Can anyone tell me if it's necessary to seal the grout in a shower? My ensuite bathroom is 13 years old and I don't think the grout has ever been sealed but I recently came across discussions on the internet about sealing the grout every year or so to prevent the possibility of water penetration. Didn't know if it was worth buying some grout sealer to do this or not.
Thanks.

Hi,
First and foremost, tile and grout are not waterproof. All tiles and grout will hold water to varying degrees.
Once the tiles have been laid you should always, in my opinion use a sealer for tiles and grout. Depending on what tiles you are using will depend on how often you seal the tiles and grout.
After 13 years it may be a waste of time and money but for piece of mind there would be no harm in sealing the tiles now.
I hope this helps? Ian@ JRHConstruction

Rubbish!

How is a ceramic, quarry or any other tile not be virtue of its fired hard state not water proof.

The weak link is the grout, although for years modern grout has had better qualities and when set and new is very waterproof. Over years and years grout can break down due to constant damp, constant wet, bleach, soaps and cleaning chemicals.

If the grout when dry is powdery or soft it needs replacing. The choice is either a full re-tile or digging out enough grout to re-grout all tile joins.

Post up a picture. And please ignore the previous answers, which might be misplaced due to him not noting the tiles are in a shower and so will be non porous ceramics.

The grout doesn't seem soft or flaky.
A few months ago I went over the existing grout with some ready made grout just to hide discolouration (I know this probably wasn't the best idea)- some of the new stuff has flaked off a bit but original seems fine.
Here are some pics

Hello,
You're certainly entitled to your opinion Chri5 and I'm sure you're aware that
quarry tile is produced by a high-pressure extrusion process. This forms a dense, strong tile that will absorb less than 5 percent of its own weight in water. You can use quarry tile on floors and kitchen countertops because it is water resistant, although not waterproof. Unlike porcelain, quarry tile should be coated with a protective sealing compound when used in applications that frequently expose it to water.
A tile is considered porcelain if it will absorb less than 0.5 percent of its own weight in water. Typically, porcelain is very dense and strong. For that reason porcelain is ideal for use in areas with lots of water like bathrooms, shower stalls or kitchens, or in rooms where dampness is a problem.
The surface of most ceramic and porcelain tile does not need to be sealed, although some require a light application of a penetrating sealer to fill the micro pores on the surface of the tile. However, the grout joint between the tiles is usually very porous and generally made of a cement-based material and should be sealed.
In the original post there's no mention to flaky grout. I agree that if the grout is flaky it should be replaced. I would also say that this could be a perfect opportunity to remodel the bathroom depending on budget.