To recharge enchanted weapons in The Elder Scrolls IV: Oblivion, you have several methods available:

• Using Soul Gems: This is the most common and cost-effective way. You need filled Soul Gems in your inventory to recharge your weapon. To fill Soul Gems, cast the Soul Trap spell on an enemy and kill it, which captures its soul. Different Soul Gems hold different sizes of souls, with larger ones providing more charge. Filled Soul Gems can then be used to restore your weapon's charge

• Using Azura's Star: Completing Azura's Daedric quest rewards you with Azura's Star, a reusable Soul Gem that can trap souls of all sizes and does not break after use. This is a convenient alternative to regular Soul Gems

• Using Varla Stones: These rare items, found in Ayleid Ruins, fully recharge all enchanted weapons in your inventory at once. They are best saved for later in the game when you have multiple powerful enchanted weapons. Varla Stones are single-use and do not respawn

• Paying a Recharger: You can pay NPCs at Mages Guild Halls or the Arcane University to recharge your weapons for a fee. This method is straightforward but expensive, so it's less recommended unless you're in a pinch

To summarize, the preferred approach is to fill and use Soul Gems or Azura's Star for recharging, save Varla Stones for bulk recharges, and use paid services only when necessary. Make sure to keep some empty Soul Gems and the Soul Trap spell handy to capture souls yourself for recharging. This system helps maintain your enchanted weapons' effectiveness as their charges deplete with use