A durability of 2.5 is 120 shots. Putts made on the green don't decrease durability & in practice mode choosing the Mulligan option decreases ball durability (even putts) by 2 shots instead of only 1 shot. See chart below. Also. Do not under any circumstances use the forum Search feature.
http://www.wgt.com/forums/search.aspx?q=ball%20durability
There is no true length. The published distance of a club is an approximation because so many variable factors effect the actual distance a shot will go - full or partial swing, hit on Ding or missed the ding, wind speed & direction, ball spin setting, the terrain & surface where the ball lands.
Top spin generally adds length because a ball rolls out further after landing.
Back spin generally subtracts length by making the trajectory of the ball higher.
Depending on the club, the wind, and the terrain. Hitting a Driver adding top spin usually will subtract length and using back spin will add length.
Using top spin into the wind adds less length than using top spin with the wind.
Using back spin against the wind subtracts even more length, and can make a shot using a short club back up A LOT more than you expect.
As an example consider the tee shot at #18 on St. Andrews. Many players hit driver off the tee with full top spin but use less than a full swing because they are trying to land the ball on the paved path that bisects the fairway as a way to get lots more distance on their drive. Accomplished players are often able to drive the green by doing that.
The following ball durability chart chart was
compiled earlier this year by a few members of The Peoples Club:
Brand
|
Ball
|
Level-Tier
|
Credits
per Sleeve
|
Durability
|
Hits*
|
9-hole
round
per ball**
|
Credits
per
9-hole round
|
Callaway
|
Tour i(s)
|
33+
|
250
|
2.5
|
120
|
5.70
|
14.62
|
Callaway
|
Tour i(s)
|
Legend+
|
250
|
2.0
|
100
|
4.66
|
17.88
|
Callaway
|
Tour i(z)
|
35+
|
300
|
2.5
|
120
|
5.70
|
17.54
|
Callaway
|
Tour i(z)
|
Legend+
|
300
|
2.0
|
100
|
4.66
|
21.01
|
Callaway
|
Tour i(z) Slow Meter
|
1+
|
300
|
2.5
|
|
|
|
Callaway
|
Tour i(z) Slow Meter
|
34+
|
450
|
2.5
|
|
|
|
MAX
|
Slow Meter
|
Hack+
|
450
|
2.0
|
|
|
|
MAX
|
Slow Meter
|
Pro+
|
600
|
2.0
|
|
|
|
Nike
|
20XI-S
|
47+
|
400
|
2.5
|
120
|
5.71
|
23.35
|
Nike
|
20XI-S
|
70+
|
450
|
2.5
|
|
|
|
Nike
|
20XI-X
|
48+
|
400
|
2.5
|
118
|
5.62
|
23.72
|
Nike
|
20XI-X
|
71+
|
450
|
2.5
|
|
|
|
Srixon
|
Z-STAR
|
11+
|
180
|
2.5
|
120
|
5.71
|
10.5
|
Srixon
|
Z-STAR XV
|
13+
|
200
|
2.5
|
120
|
5.71
|
11.67
|
Brand
|
Ball
|
Level-Tier
|
Credits
per Sleeve
|
Durability
|
Hits*
|
9-hole
round
per ball**
|
Credits
per
9-hole round
|
WGT
|
B-ES
|
Any
|
10
|
2.0
|
125
|
5.95
|
0.56
|
WGT
|
B-XD
|
Any
|
10
|
2.5
|
150
|
7.14
|
0.47
|
WGT
|
Tour-S
|
Any
|
43
|
1.5
|
100
|
4.76
|
3.01
|
WGT
|
GI-S
|
Any
|
44
|
2.0
|
120
|
5.70
|
2.57
|
WGT
|
GI-D
|
Any
|
49
|
2.0
|
|
|
|
WGT
|
GI2-S
|
Any
|
64
|
2.0
|
125
|
5.95
|
3.59
|
WGT
|
GI2-D
|
Any
|
64
|
1.5
|
|
|
|
WGT
|
Tour-SD
|
Any
|
65
|
1.5
|
110
|
5.24
|
4.13
|
WGT
|
Tour GI-S
|
Any
|
82
|
1.0
|
90
|
4.28
|
6.37
|
WGT
|
Tour GI-SD
|
Any
|
112
|
1.0
|
90
|
4.28
|
8.72
|
WGT
|
GI3-S
|
Any
|
99
|
2.0
|
125
|
6.00
|
5.5
|
WGT
|
GI3-D
|
Any
|
94
|
1.5
|
110
|
5.24
|
6.0
|
WGT
|
GI-SD2
|
Legend+
|
120
|
1.0
|
|
|
|
WGT
|
GI2-SD2
|
Legend+
|
155
|
1.5
|
95
|
4.52
|
11.43
|
WGT
|
Starter Slow Meter
|
Any
|
100
|
1.0
|
|
|
|
|
|
|
|
|
|
|
|
* Putts do not count as hits & are not
included, except putts from the fringe.
** Calculated based on 21 hits per 9-hole round
(par 36 with 67% green-in-regulation).
There are a few empty fields and the new Nike
balls aren't listed, but I can atest to the accuracy of the statistics.
As you can see, dots of durability as provided
by WGT can be a bit inaccurate.