This is something many new football traders have trouble with.
The most important point for me is to be consistent.
Some of us are more cautious than others. Some like a greater degree of risk where others prefer less. Either way is fine, but you must be consistent.
Personally, I am more of a cautious trader, although can exceed a one point loss if I think the in-play stats look good enough to justify it.
As a rule though I will do the following with a LTD trade.
If a game is 0-0/1-1/2-2 at HT, I will generally wait until around 65′ before trading out for a loss. If there is a goal before 65′ I will trade out straight away.
If a game is 1-0/0-1 at HT, I will generally trade out unless I can see that the team that is leading is completely dominant in the game in which case I will leave it until up to 65′. Most cases though I will trade out.
If either team take a 2-0 lead I will usually trade out straight away. In some cases I may stay in if the leading team is dominating play.
If the favourite in the match is short-priced and take the lead, I may trade out straight away for an instant profit.
Some traders will hang on regardless until at least 65′ or if the draw odds drop to 2.0, but I prefer to manage the days profits/losses. If I am having a good day I would rather not risk my profits by waiting until 65-70′ only to see a team equalise and the game end in a draw.
Horses for courses. I would say find your way and stick with it. Be consistent!
If you swap and change things around constantly, you will not be able to assess correctly how well your system is ultimately performing and knowing this is crucial to long term profits and success.
Good luck!