Auto-incrementing a value with UIButton and NSTimer or just use UIStepper

ViewController-snippet.m

@interface ViewController

@property (nonatomic, weak) IBOutlet UILabel *numberLabel;
@property (nonatomic, strong) NSTimer *numberTimer;
@property (nonatomic, assign) double value;
@property (nonatomic, assign) BOOL cancelTimer;
@property (nonatomic, assign) NSTimeInterval timeInterval;

- (void)updateNumberLabel;
- (void)stopTimer;

- (IBAction)longPress:(id)sender;
- (IBAction)touchUpInside:(id)sender;
- (IBAction)touchDragExit:(id)sender;
- (IBAction)touchCancel:(id)sender;

@end

@implementation ViewController

- (void)updateNumberLabel
{
    self.numberLabel.text = [NSString stringWithFormat:@"%d", [@(self.value) intValue]];
}

- (void)stopTimer
{
    self.cancelTimer = YES;
    if (self.numberTimer) {
        [self.numberTimer invalidate];
        self.numberTimer = nil;
        self.timeInterval = 0;
    }

    [self updateNumberLabel];
}

- (IBAction)addNumber:(id)sender
{
    NSTimeInterval newInterval =  self.timeInterval ?: 1;
    
    if (self.numberTimer) {
        newInterval = MAX(0.02, newInterval - newInterval * 0.2);
    }

    if (self.cancelTimer) {
        [self stopTimer];
        return;
    }
    
    self.value += 1;
    
    [self updateNumberLabel];
    
    self.timeInterval = newInterval;
    
    NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:newInterval target:self selector:@selector(addNumber:) userInfo:nil repeats:NO];
    
    self.numberTimer = timer;
}

- (IBAction)longPress:(id)sender
{
    UILongPressGestureRecognizer *gr = (UILongPressGestureRecognizer *)sender;
    CGPoint touchLocation = [gr locationInView:self.view];

    BOOL touchInButton = CGRectContainsPoint(gr.view.frame, touchLocation);
    
    if (!self.numberTimer && touchInButton) {
        self.cancelTimer = NO;
        [self addNumber:nil];
    }
}

- (IBAction)touchUpInside:(id)sender
{
    [self stopTimer];
}

- (IBAction)touchDragExit:(id)sender
{
    [self stopTimer];
}

- (IBAction)touchCancel:(id)sender {
    [self stopTimer];
}

@end