Yes and No
Yes because you don't do anything academically and No because you get to Experience new things like "Work Exp" , "Army", "First Aid" , "TYPE" (TY Physics Education, up in trinity for the week) etc.
I did TY and I'm now in Sixth Year and I regret taken a year out but then I don't because I learnt a lot as well such as doing the trips and going away from the week learning other stuff for a change was cool :) But a lot of 5th year student who did TY will say they wish they skipped because they lost motivation and concentration in class to do the work given to them. Some say their motivation and concentration levels didn't start coming back till the Final Term of school!
But look everyone's different, TY might not be for you and 5th year maybe? Who knows unless you try it out!
It depends what you do with it. I know people who went into ty to do nothing and didn't like it because they didn't put themselves forward for anything and were bored and thought it was crap. I also know people who did ty (including me) that loved it because they got involved with the projects and stuff that went on. And don't listen to the "ty made me not able to study" because that is the biggest load of a bs excuse that has ever existed. If your'e motivated to study in fifth year then you're motivated and if you're not, doing ty won't make any difference. I was able to concentrate better and study better after the year's break. I did it and it was the best thing I ever did
Get involved in loads of projects and clubs and stuff and you'll have the best year of your life :) If you spend the year doing nothing you will get bored very quickly and wish you had skipped. I did Ty and I'm in 6th year now and I don't regret doing it at all
this is my 3rd week of it, so far I absolutely adore it. You have to really put yourself out there or else you won't enjoy it, it's only lazy if you make it lazy, use all your time wisely, try out every single activity, learn a new language, absolutely anything it's all about doing things for yourself rather than following the crowd.
Honestly, you don't really need to its surprisingly easy to get back into it. Maybe read some of the texts you could do for English read into a few topics for science subjects. One thing I would say is to keep on your foreign language as best you can because you will forget a good bit and while its not that hard to get it back again its something easily avoided