Internal practices are going to be the most important in regards to hair growth and hair loss. For example- diet, lowering stress, boosting blood flow, sleep schedule, and so on! Usually, when making these kinds of changes to your routine, you should start to see improvements in your hair after about 3-4 months of remaining consistent with these changes. Other hair issues such as dryness, scalp conditions, etc... it is more about figuring out whether something in your routine is causing this reaction and what changes you can make to improve it. Once you find what you should change and make those changes in your routine, you should be able to see improvements quite quickly. Ultimately, if you have been losing hair for a long time, it might take longer to regain your density to what it was before; however, it is not impossible; you have to remain as motivated and consistent as you can.