Murray Barber from The Mill a VFX company down in London did a talk at Animex which I found really relevant and useful for the visual effects module I'm currently working on. Because The Mill does a lot of visual effects for TV, Murray spoke about how they achieved their effects on a budget and a tight deadline. Budget actually plays a big part within TV as it will determine what can be included and if there is time to create something large scale. To overcome this they tend to re-use assets from previous shows, altering them slightly to fit in with their new surroundings. Working in TV, you build up a vast asset library which you need to use to your advantage, it saves time and that time saved can be spent on something that require more detail and effort. Because of time constraints it's best to try and get involved in the script writing stage if possible, this then allows communication between the studio and script writer to advise them what is achievable for the budget and time scale.
Below is a quick making of from The Mill of series 5 of Doctor Who, you can see that even with the time restrictions and budget they are still able to create high end visual effects. Instead of creating numerous amount of set extensions, they use matte paintings, something that requires less work yet produces the same visual effect. It's tricks like these that can work in your favour, why model every tiny detail when it will only be seen from far away.
Working in TV is very much fast paced, especially commercials. In film, you would get far longer working on a section and have the time to make every detail perfect. TV, you have to find the right balance of sending it out on time yet also creating something visually appealing that will grab the audiences attention.