Crystal Disk caution on Reallocated Sectors

HD passes Data Lifeguard extended CD test. How serious would you rate the Caution CDI is giving for Reallocated Sectors?

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CrystalDiskInfo 3.10.0 (C) 2008-2010 hiyohiyo
Crystal Dew World : Crystal Dew World
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OS : Windows 7 Ultimate Edition SP1 [6.1 Build 7601] (x86)
Date : 2011/06/08 20:08:03

-- Controller Map ----------------------------------------------------------
+ ATA Channel 0 (0) [ATA]
- WDC WD800BB-53CAA0 ATA Device
+ ATA Channel 1 (1) [ATA]
- HL-DT-ST DVD-ROM GDR8160B ATA Device
+ Intel(R) 82801DB Ultra ATA Storage Controller-24CB [ATA]
- ATA Channel 0 (0)
- ATA Channel 1 (1)

-- Disk List ---------------------------------------------------------------
(1) WDC WD800BB-53CAA0 : 80.0 GB [0-0-0, pd1]

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(1) WDC WD800BB-53CAA0
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Model : WDC WD800BB-53CAA0
Firmware : 16.06V16
Serial Number : WD-WMA8E1469232
Disk Size : 80.0 GB (8.4/80.0/----)
Buffer Size : 2048 KB
Queue Depth : 1
# of Sectors : 156301488
Rotation Rate : Unknown
Interface : Parallel ATA
Major Version : ATA/ATAPI-5
Minor Version : ----
Transfer Mode : Ultra DMA/100
Power On Hours : 21866 hours
Power On Count : 6644 count
Temparature : Unknown
Health Status : Caution
Features : S.M.A.R.T., AAM
APM Level : ----
AAM Level : 80FEh [OFF]

-- S.M.A.R.T. --------------------------------------------------------------
ID Cur Wor Thr RawValues(6) Attribute Name
01 200 200 _51 000000000000 Read Error Rate
03 _93 _92 _21 000000001138 Spin-Up Time
04 _94 _94 _40 000000001ADA Start/Stop Count
05 196 196 140 000000000034 Reallocated Sectors Count
07 100 253 _51 000000000000 Seek Error Rate
09 _71 _71 __0 00000000556A Power-On Hours
0A 100 100 _51 000000000000 Spin Retry Count
0B 100 100 _51 000000000000 Recalibration Retries
0C _94 _94 __0 0000000019F4 Power Cycle Count
C4 198 198 __0 000000000002 Reallocation Event Count
C5 200 200 __0 000000000000 Current Pending Sector Count
C6 200 200 __0 000000000000 Uncorrectable Sector Count
C7 200 253 __0 000000000000 UltraDMA CRC Error Count
C8 200 200 _51 000000000000 Write Error Rate

-- IDENTIFY_DEVICE ---------------------------------------------------------
+0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +A +B +C +D +E +F
000: 42 7A 3F FF 00 00 00 10 E1 00 02 58 00 3F 00 10
010: 00 00 00 0E 57 44 2D 57 4D 41 38 45 31 34 36 39
020: 32 33 32 00 00 00 00 00 00 03 10 00 00 28 31 36
030: 2E 30 36 56 31 36 57 44 43 20 57 44 38 30 30 42
040: 42 2D 35 33 43 41 41 30 20 20 20 20 20 20 20 20
050: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 80 10
060: 00 00 2F 00 40 01 02 80 00 00 00 07 3F FF 00 10
070: 00 3F FC 10 00 FB 01 10 F8 B0 09 50 00 00 00 07
080: 00 03 00 78 00 78 00 78 00 78 00 00 00 00 00 00
090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0A0: 00 3E 00 00 34 6B 4B 01 40 00 34 69 08 01 40 00
0B0: 20 3F 00 00 00 00 00 00 00 00 60 4D 80 FE 00 00
0C0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
100: 00 09 00 00 00 00 00 00 00 00 00 2D 00 00 00 00
110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 1E
140: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
160: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
170: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1A0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1B0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1C0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 EC A5

52 seems pretty high to me. How old is it? But if, as I expect you do, keep a current image backup, meh.

Stock HD on a Best Buy premium house build VPR Matrix Pentium 4 which still runs great after 24/7 service for ten years with only a PSU change, with Dual Monitors driven off a Radeon 9500.

I don't think the absolute static value is as important as how it changes over time.
Note: DCI settings
Function > Health Status Warning > Threshold of Caution
"Reallocated Sector Counts" are one of 3 sector counts that the user can set the "Threshold of Caution" for.

I would set it to some value slightly higher than the current value. If it creeps up to this in an unacceptable period of time then you have a problem.

So to answer your question
"How serious would you rate the Caution CDI is giving for Reallocated Sectors?"
It's your judgement call.

I wouldnt be worried at this stage. The reallocated sector count is 52 which may or may not indicate anything unless there are accompanying bad signs such as stalling or clicking.

More importantly, other significant counts are zero- seek error rate (this'll be a positive figure if theres a mechanical positioning problem or a thermal widening of the platters), the spin retry count (number of attemts to reach full speed), the current pending sector count ( number of unstable sectors waiting to be mapped) and the uncorrectable sector count (self explanatory).

Interestingly, the reallocation event count is only 2 which means that there have been only 2 attempts to transfer data from the bad sectors to spare ones.

This drive appears to be at least about 3 years old and a certain no. of bad sectors would be normal. As usual keep your data backed up and run crystaldisk or whatever occasionally to check for sudden deterioration.