Shops are usually only open in the morning on Saturday. In larger cities, shops are usually open later, for example until 8 or 9 pm. The smallest shops sometimes have a break for lunch, usually between 12 noon to 1 pm.
Hypermarkets and shopping centres are usually open 7 days a week until 9 pm, often even on public holidays. Some shops and petrol stations operate almost nonstop (other than the early hours of the morning).
Banks are regularly open on weekdays during working hours. Busy branches in city centres are usually open later, for example until 8 pm. Access to cash machines is ensured 24 hours a day.
Monday and Wednesday are standard office days for authorities, from 9 am until 5 pm. Some authorities provide services for the public on other days too although offices are usually closed over lunch (often from 12 noon until 1 pm).
The main provider of postal services in the Czech Republic is Czech Post. They deliver consignments all over the world. You can calculate prices here.
Post Offices are regularly open from 8 am to 7 pm and in large cities you will find branches which are open almost nonstop.
Apart from Czech Post, a network of postal and courier companies exists in the Czech Republic, which try to ensure the fastest possible delivery of consignments for their customers.