Fortune is one of those fickle elements of Warhammer Fantasy Roleplay. Since the number of Fortune Points you have per day is based on the number of Fate Points you have remaining, the longer you eke out a living in the Old World, chances are the fewer Fortune Points you're going to have to play with.
Sure, Fate Points can be awarded for completing epic quests and for monumental achievements, but the burn rate can be pretty high, as well. One Ulric's Fury to the face from an Orc Warboss' battleaxe, and your scratching off a Fate Point or pushing up the daisies. Considering some races can start out with a single, lonely Fate Point, some players feel they need to horde the use of their precious few Fortune Points.
To recap: mechanically, Fortune Points can be used in one of four different ways:
1. Re-roll one failed Characteristic or Skill Test. (Note, this specifically states you can re-roll a test — not a Tzeentch's Curse result, not a damage roll, etc)
2. Gain an extra Parry or Dodge — which allows a player to Parry or Dodge more than once per round (which is normally forbidden).
3. Roll an extra 1d10 for Initiative to determine combat order.
4. Gain an extra half action during your character's turn in combat.
Based on my own experience and from talking to other players, it seems that most often Fortune Points are used for that first option — re-rolling a failed test. And not just any test, but it almost always seems to be a Weapon Skill or Ballistic Skill test when that hit is really, really needed to take someone down, or a Dodge or Parry to avoid that nasty blow you know is coming (and failing the Dodge/Parry could mean permanently burning a Fate Point if it's an especially nasty attack).
While those are definitely good uses of Fortune Points, some players feel a bit constrained. There are a lot of tactical options available if you have more Fortune Points — spending a Fortune Point for an extra half action to move into position or aim can have a huge impact on battle, or even reducing your reload time for that blunderbuss you tote around. But when you're down to just one, those tactical options start to pale in comparison to that chance to save your hide at the last moment.
I've also never personally seen a player use a Fortune Point to roll an extra 1d10 for Initiative before combat. Ever. It's too great a risk, since a character could roll so poorly the Fortune Point is essentially wasted.
So what are some options? There are as many different house rules and ideas on Fortune and Fate as there are players. Here are some I like to use:
Fortunate Characters: As soon as a character completes his first career (all advances), he automatically gains the Fortunate talent for free. The Fortunate talent is literally just the Luck talent with a different name — this allows a character with access to the Luck talent the option to still pick it up so it stacks. After all, if you've survived this long, you're doing something right.
New FP Use — Ulric's Fury: I've added a Fortune Point option which allows a player to spend a Fortune Point to automatically confirm an Ulric's Fury check after rolling a "10" for damage, rather than having to re-roll their attack roll to see if it's triggered. This is especially helpful for characters with a low WS or BS that got that lucky hit in.
Fortune Points as Bennies: I like to view Fortune Points as an additional resource GMs have at their disposal to reward players for clever plans, good roleplaying and helping to drive the narrative. Tossing a Fortune Point to a player for quick-thinking is a great way to encourage that sort of creativity in a group. Since Fortune Points "reset" each day, it also encourages players to use those extra Fortune Points lest they be lost.