A 7 card GOOD suit is typically trumps. Don't get carried away with a 7 card bad suit. Lets compare two hands.
Despite having a heart fit, you have a 7 card suit which is a 1 loser suit, that should be trumps.
a 0-1 loser 7 card suit should (almost) always be trumps. Even if you have another fit.
Example hand 2 - a bad 7 card suit.
For this pair, 2♠ showed a 6th spade. What would you do from there? As for making contracts - 6♠ makes whereas 4♥ is one off.
It is important to not get carried away with a bad suit.
The most important signals
Double or bid?
Bid as high as possible!
Defending against a multi 2♦
Transfer or not?
Nv compete
How strong vulnerable?
Preempt suit quality
6322 and 7222
2♣ opening
Doubleton lead
Passive lead
When to lead active
1N with 5422
Takeout double
Negative double
Splinters
Competing partscore
Try not double
Ace Ace King
2 level overcall
Lead Trumps #1
Lead Trumps #2
7 card GOOD suit
To open or not, pre-empt or not
Let the opponents play when they are misfitting
The strongest hand
Be practical