When buying an item online you may look at the delivery options to see which one suits your needs. Many companies offer a next day delivery service and recently some have even started offering same day delivery! If the item is being sent by royal mail post then it is usually recorded, tracked, 1st class or 2nd class. Recorded delivery is not guaranteed for the next day (many people get this confused), it just means that someone will need to sign for the item. Tracked items are usually delivered the next working day and you can chose if you need it delivered before a certain time. 1st class is often 1 -2 working days in the UK and second class 2- 4 working days. This said, apart from the tracked service none of the others are guaranteed, so you could be waiting weeks for that parcel to arrive. The post office will not investigate a missing letter or parcel until after 28 days and even then, if it has no tracking number it will be very hard for them to find out where it has gone.
So is it worth paying for faster delivery? Only really if it is guaranteed.