Deadlines can be a helpful way to get a lot of things done. But they can also work against us in many ways.

Stop Procrastinating

This is one of the reasons it's great to set deadlines a little closer than you'd want. It's easy to procrastinate something when it's a couple of month or year stretch. Like long-term goals are a good example of this. It's so easy to put the discomfort of chasing those goals off. Because it's so far away.
This is also why it's important to have mid-term and short-term goals that go along with our long-term goals. So we are more likely to be on track to get those long-term goals.

Lose Your Sense Of Urgency

When you set deadlines that are far away, you lose that sense of urgency. Instead of accomplishing the goal sooner, You are more likely to accomplish it later. Just because you can.It doesn't seem as urgent or important. This is especially true when we don't have a deadline set at all for our desired goal. When things have no deadline, they often don't get done. Haven't you noticed you are more likely to gravitate to the homework assignment Or go to work? Well, that's because it has a deadline. Why cut yourself short with the most important goals of your life? Not your employers, Not Your Schooling, But your own goals that get you closer to your purpose in life, Your dreams.

Conclusion

Deadlines can be good or bad; Long-term deadlines can sometimes cause more harm than good and having no deadlines also causes problems. When setting a deadline for a goal, I always recommend giving yourself a little less time than you'll think it will take. But don't go overboard. If you are never able to accomplish your goals on time. That will send a message to your subconscious that you aren't very good at getting things done. It will also hurt your self-esteem.
If you need to accomplish something you've already accomplished before, Try setting a timer and seeing how long it takes. I often do this with my cleaning/Chores.
For example, It takes me about 25 Minutes to clean rabbits cages,
About 13 minutes to clean my room.
And another 10-15 minutes to do the dishes. So I expect myself to get all that done in an hour is a reasonable goal.