Ar first, I needed therapy so badly because I had been a complete disaster for so long that I probably was going to finally succeed at drinking myself to death within weeks. In fact, my therapist commented on the fact she thought I might not live long enough to see her the second week. Her diagnosis- severe gender dysphoria, major depression, anxiety, ADD, alcohol and drug abuse.
I did 50 minutes every Saturday afternoon for the first couple of months. I was put on a low dose of estrogen after one month. I felt much better right away, and was eventually able to kick the antidepressants and antianxiety meds. My therapist told me I was "cured" after 3 months and I went on my merry way.
The estrogen was simply the most amazing thing. It made me feel so wonderfully girly 24/7 that I made the decision to attempt going full time and possibly transition fully after around week 8. For this my endo was going to need letters, so back to the therapist for 5 more sessions. The last two of these were mostly spent talking about our mutual fondness for fine wines and heavy metal. I got the letter and off I went.
A few months later I needed the SRS letter, so I had two more sessions that were nothing more than a formality. I have graduated from therapy.
I was incredibly fortunate that being trans didn't really have any negative impact on my life, other than the whole being trans thing itself. The collateral damage of gender dysphoria can sometimes be absolutely devastating, and this is why I think I got away with so little therapy.
Some people see a therapist more than once a week for years. I know plenty of cispeople who do or did.
Your issues are unique to you, and a good therapist is invaluable in getting them sorted out as quickly as possible. I probably owe mine my life.