It really does depend on the development - how well run it is generally, whether there are a lot of problems and issues to sort and how many neighbours are on the residents committee. Many hands make light work!
On our committee we find it's easier to split the various jobs between people ie; one person will look after car parking, another will be responsible for communications etc. And if there's a particular project someone will lead on it with help as necessary.
So, as the previous poster said, it's often a flurry of activity in bursts rather than a hugely onerous ongoing committment. We meet monthly for a couple of hours but you may not need to meet that frequently.
Being a Company Director (rather than just being on the committee) does come with more responsibility though and you do need to commit to it for a reasonable length of time. Some recent posts here have rightly pointed out the many legal implications but I would urge you not to be put off.
We ask that anyone interested in being on the Board serves on the committee for 6 months to a year so they get a good idea of what they will be taking on and also to demonstrate their commitment and dependability.
Why not give it a go? You can explain in advance how much time you'll be able to commit to and if you find it's too much you can always bow out after 6 months.
I would definitely encourage you to take part. It takes a bit of time and effort but there are compensations. It's great knowing that you have contributed positively to your environment. It's good to know where your management fees are going and ensuring the money's spent wisely, and at least you get to know a few of your neighbours if you ever need the proverbial cup of sugar!