This pattern is very good for people who want to move on to Yang style tai chi forms because it introduces the basic elements of weight shifting, co-ordination of hand and leg movements together with controlled breathing.
All shibashi movement is centred around a face forward position. Diagonal side steps always return to this starting position - so in that sense it is fixed. If you can stretch your arms out to the sides and turn a full circle you have enough space to practice.
The complete shi ba shi pattern takes about 15 to 20 minutes depending on how you are feeling.
It's suitable for all groups and all ages - and you are never to old to start - we recently worked with a lady who said she stopped counting at 70 - and she loved it.
As always it is better to practice every day even for just 15 minutes than to do an hour twice a week.