Almost everyone who has finished a PhD would say that it was only when they had finished that they really saw how it should have been done. If this is what you're feeling, but have sufficient evidence to know that the work is good enough as it is, don't worry. All the insights you gain doing your PhD research don't have to be used to improve this particular work. You will use this knowledge, skills and experience in your future work.
The important questions to answer are: how crucial is the change you're thinking about? And, what are the consequences of not making such changes? If not making the change means that it is doubtful whether your work will be of acceptable standard, then no matter at what stage of your research you're at, or how much work is involved in the change, you have to make it. Since this is such an important and profound decision you shouldn't make it alone; therefore discuss it fully with your supervisor. Of course any change will lead you to consideration of other constraints, such as time, cost, and your own financial situation. If on the other hand the gains are slight but the proposed change would involve a lot of work, then maybe you should accept the work as it stands.
Sometimes the change you are contemplating will have a major impact, even to the point of overturning your original stance, and yet it will not necessarily involve an excessive amount of work. The work is in the thinking and re-conceptualising. This is probably worth doing.
It is almost always possible to find ways of improving your work, and up to a point this is a necessary part of reviewing, re-examining, redrafting your thesis. However avoid being sucked into an endless process of making minor changes for only small gain when your PhD thesis has reached the point when it should be submitted. It could just be reluctance to let go and face what happens next.
|How do I know if I have done enough, or if my work is good enough for a PhD?|
|Seeking, receiving and handling feedback.|
|Strategies for getting the best feedback possible.|
|Overcoming reluctance to seek feedback.|